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Community and Q&A

User Reviews of Chiltrix Air-to-Water Heat Pump

JesseTrinque | Posted in Mechanicals on

First question on GBA even though I’ve been a dedicated reader for over a year.

Anyway, My wife and I are in process of building our house and I’m starting to research more into the Chiltrix unit (again) and would love to hear a real owners story. Everything sounds great online (by way of google) but can’t find any real reviews or someone crazy enough to pull the trigger on the unit. I currently have calls into both spacepak and Chiltrix/hotspot energy, and I’m getting serious about this option, more-so on the chiltrix…

I’m building a tight, well insulated 2500sqft ecopanels SIPS house in Northeast CT CZ5A and have tubing already installed in the 1st floor and basement/garage slab with loops for low temp panel rads upstairs. I was planning to go with a high end condensing gas boiler setup (propane), and I have roughed in ductwork up to the conditioned CC SPF attic for a central return downfeed system.  I am designing and building this house all myself and the original plan was a small standalone conventional A/C system in the attic completely disconnected from the Heating system, i.e. no hydro air. My wife and I despise forced hot air heat – we’ve lived in two houses with it and one without, hence the hydronics.  I explored the chiltrix and Spacepak systems early on and kind of determined that I couldn’t afford the risk of being a pioneer, however – its basically time to pull the trigger on equipment, the mechanical engineer in me demands I explore these options again, and the more I look the attractive they sound. The monobloc config (and price) of the Chiltrix unit have me intrigued since I could probably do most of the work myself. The company also seems to be DIY friendly by their website anyway, I’m still waiting to see what their customer service is like as that may be a determining factor.  Another side benefit for me would be being able to use this for the Airhandler in the attic for cooling loads, gaining me a variable speed/higher efficiency A/C system then the simple on/off 2 ton unit I was going to install, and I can justify the price for heating by ‘eliminating’ (more-s0 replacing) some A/C equipment I was going to purchase seperately. Btw, my cooling loads are sub 2ton and should fit the Chilltrix specs nicely. I’m realizing that this unit won’t do all my heating loads but I’m thinking I could do a (less expensive) propane boiler, I was planning on Viesmann, and run my higher temp circuits/DHW via indirect on the boiler and just let the chiltrix do the radiant floors separately. I could also get much fancier and integrate the systems, advantages and disadvantages to both routes. Either way, this would allow for some redundancy and could also put a fan coil head in the garage and basement for cooling which would be awesome. My googling skills and GBA have told me that these units are basically a bunch of really high end parts cobbled together in an awesome little unit that could fit my needs really well. The problem being is whether this is going to be something I will have problems with for the next decade?? Do they work as advertised? I would really love to hear from an actual installer/end user of one of these systems. I think that would be enough to make me pull the trigger. There are alot of older similar threads to mine on GBA and I’m wondering if someone since then has pulled the trigger on one.

Most mechanical companies I see and deal with either think an option like this is stupid, don’t know enough about them, or want a premium to explore it at my expense.


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  1. cr0ntab | | #1

    Subscribing to responses.

  2. Expert Member
    Dana Dorsett | | #2

    "My wife and I despise forced hot air heat – we’ve lived in two houses with it and one without, hence the hydronics."

    I'll go out on a limb here and guess that the forced hot air was NOT modulating (probably not condensing either) and 3-5x oversized for the peak heating load, with a leaky/noisy air handler & duct system. That's been the industry standard, and it's easy to despise. A sample size of one isn't going to tell you much about what CAN be done with a hot air approach.

    A two stage right-sized condensing fossil-burner hot air with a tight Manual-D duct design is a whole other animal entirely. It's far quieter, and runs more moderate exit air temperatures at lower cfm for much longer duty cycles.

    About four years ago I ended up advising on a ~4000' house (2000' of finished walk-out basement) in Worcester, MA . This house came with radiant floors in the lower level & radiant ceilings in the upper level. But it was a mid-century modern abomination for comfort, with a 8-10 tons of ducted cooling system- a duct sculpture located above the barely insulated shed-to-flat roof, and ~250KBTU/hr boiler ridiculously oversized for their loads. The house the owners had just left in a neighboring town had radiant floors & ceilings throughout, and was at the opposite end of the comfort scale. The radiant heating had been part of their buying decision. When they approached me they were trying to figure out whether they should just put the house on the market and move on, or take the bull by the horns and fix it. After a lot of discussion they opted to fix it.

    The eventual solution was to build an extremely low-height min-attic above the existing roof, with 6"of rigid polyiso above the roof deck. The mini-attic now houses a 60KBTU/hr 2 stage gas furnace and a Manual-D duct system, a separately ducted HRV system, and a cooling coil for a 4 ton air conditioning condenser on a pad on the north side of the attached garage. (The cooling load is high due to the amount of west facing glass, but they could have done fine with 3 tons.) Yes they can hear the furnace, but it's quieter than their refrigerator, but they're now convinced that even in a not-so-high-performance house hot air heating can be quite reasonable & comfortable, even if many/most hot air systems aren't.

    And YOUR wall U-factors are probably HALF those of that house! (Which Ecopanels did you go with?)

    A right sized modulating ductless or ductless mini-split system is even quieter, and even MORE stable room temperatures than best-in class hot air furnaces. I've seen people resort to installing a ribbon on the vane of a ductless head for the visual confirmation that it's actually running, since at low speed it's barely perceptible even in a quiet house.

    For the amount you're spending on a dual temp hydronic solution and separate air conditioning system in a better-than-code building envelope you're probably better off going with a mini-ducted mini-split for doored off bedroom zones, and wall coils or floor coils elsewhere. You may or may not be able to use the already roughed-in ducts.

    If the load numbers come in where I think they might, a fully modulating P-series full-sized air handler cold-climate Mitsubishi would have you covered too. The turn-down ratio isn't as high as a mini-split, but it's significantly better than 2-stage gas furnaces. Sized correctly it would run nearly 100% duty cycles during cold weather, modulating with the load. The smallest of the line that has still has the cold-climate capacity is the most likely prospect, with about a 2:1 turn-down ratio, but it might be oversized, depending on where the Manual-J came out:

    1. JesseTrinque | | #3

      "I'll go out on a limb here and guess that the forced hot air was NOT modulating (probably not condensing either) and 3-5x oversized for the peak heating load, with a leaky/noisy air handler & duct system."

      Yes, yes and yes. but that horrible system is what mama thinks forced air heat is no matter what you tell her. 5 minutes of eye-drying blasting fire followed by 20 minutes of cool breezes, then repeat. We actually still own that house and rent it and since the A/C just died a few weeks ago I will probably be ripping the whole system out in the spring for mini-splits. I also have a 36' x 98' with 10' h ceilings morton building that we rent that is conditioned solely by a dual head 48K btu fujitsu unit. This houses a manufacturing facility with some equipment (lasers) and about 6 employees.

      I wanted in the worse way to do mini-splits but my wife doesn't like the look of them ("sure they look high tech now, but what will those look like in 10 years?")- looking back some ceiling cassettes probably would have been a better decision, but alas here we are. Decisions needed to be made and they were made. Part of that is that I don't feel comfortable running minisplits DIY.

      On the flip side, we built a similar structure for my parents in Northern NH a few years back and are ecstatic with the in floor radiant even with a structure so well insulated.

      We went with the 4.5" ecopanels. we also did a CPS epitome basement system so our basement walls are 3.5" foam panels as well with provisions for more R value if we want it prior to finishing. 3.5" foam under both basement and garage slabs. I threw tubing in there as well.

      Some of the other limitations with ductwork on this house is the amount of timber framing making duct runs difficult. Low wall returns were impractical and hence why I went with the downfeed system.

      As far as cost of the systems, it was mostly materials at this point (since I only pay myself and wife $0/hr). We wanted what we wanted and could afford the labor for rough in.

      Do you have any experience with Chiltrix Dana?

      They called me back this afternoon and seem very enthusiastic and willing to do a design and work with me to get it operational. They seemed to genuinely have the right answer to the tough questions and claim to have close to 1000 units operation in NA. All replacement parts in a warehouse in VA. no certified tech needed for installation or non refrigeration related repairs.

      1. Expert Member
        Dana Dorsett | | #4

        I have zero experience with the Chilltrix. Like you, I find the specs intriguing, but an air source hydronic heat pump system seems likely to become an orphaned product in the US market.

        The Daikin Altherma looked great too, and I know of at least one installation in Maine that went well, but it was still pretty pricey, and that product is no longer offered in North America.

        I have no direct experience with the Fujitsu mini-ducted systems, but have had no problem specifying them. (So far other proposed solutions have won the day.) In a high-R house you can do a lot with one or two of those (and no wall units), and they all modulate down to 3100 BTU/hr. The 1.5 tonner is good for at least 20KBTU/hr at your design temperature. A pair would be good for 40K, which is probably more than your design load.

        The U-factor of a 4.5" Eco-panel with typical siding and interior finishes will probably come in around U0.35-U0.38, or a bit more that 1/3 the loss per square foot of a 2x4/R11 house from 1960. Your design heat losses are probably less than half that of a 2x4 house that size- probably a whole-house design load of ~20-25K(?). I assume you've been running load calculations with every design change?

        If instead of AC-only, you might consider going with a modulating heat pump, and control the floor temp with the Chilltrix, room temp with the heat pump. If it saves you the cost of the flat-panel rads and the propane boiler it might even be cheaper.

  3. lance_p | | #5

    Jesse, I'm right with you on the Chiltrix.

    I've been looking for reviews for two years and have only come across a handful of (very favorable) information. Like you, I spoke with the company (but by email) and got the same impressions - that this is a unit that does everything HVAC right, including the humidity dependent loop temperatures for continuous demand-driven dehumidification. That's a concept so simple it makes you wonder why everyone doesn't do it. Everyone with modulating equipment SHOULD do it.

    I'm in Canada, CZ6A, and that's where the deal really fell apart for me. Already I was feeling like I would be experimenting by using this system, and then they referred me to my local Hotspot dealer who had never dealt with or sold a Chiltrix system, nor did he even have pricing for the current CX34 chiller (only the previous CX30 model).

    The concept is solid, the marketing is right on target, but with "1000 systems in service" in NA where are the user reviews? They told me there ARE reviews out there but they don't bother keeping track of them. ? Why aren't these guys signing up to work with Green builders to get some exposure?

    It's actually very frustrating. Like you, I have a wife that will never go for the look of a minisplit head on the wall, and I made the mistake early on about telling her I was looking into heated floors (oops! They don't make sense in a super-insulated R50+ house). The wall mounted fan radiators were OK by her, but only just, and now I can't pull the trigger because I can't be assured I know what I'm getting into. What a bummer! We're closing in on getting our building permit and I'm leaning towards a fully modulating gas furnace... the easy way out, but with IMPECCABLE ductwork and none of the one-speed-full-power-fan-ON blast we're all too familiar with.

    BTW, the system we're looking at is from Dettson, a company in Quebec. They make small (15k BTU and up) 40-100% modulating gas furnaces that use modulating heat pumps for air conditioners, therefore allowing a "dual-fuel" approach to heating the house.

    Please share if you do find any encouraging info on the Chiltrix. It's a very cool looking system that I hope gains traction in the market, as well as some sort of presence in Canada.


    1. lance_p | | #7

      It's been a while since I've been on Chiltrix's website, and now I see they have a new V18 backup heat system.

      This looks like the perfect answer to cold climate use, one of the sticking points with using it in our application. Darn it, every time I go to their website I get excited about that system!

  4. JesseTrinque | | #6

    I talked to John at Chiltrix, I'm going to provide the manual J for him and he offered to do a design and quote. Its like the magic box that does exactly what I want it to do, it seems to good to be true. Price-wise it seems logical. I feel like I'm missing something, and I have a bad feeling that something is that its a piece of Junk that I'm going to be throwing in the dumpster in 2 1/2 years. But with 1000 units out there can that be true? Did you look at a couple of the youtube videos? Their controller looks pretty amazing and the de-humidification seems top notch. Awesome principle. I'm not sure I'm up to being a guinea pig, i think the only way I would do it with with a redundant boiler setup, and then I wonder if I'm just better off spending the extra money on the propane sipping viessmann 200 for the dual temp setup. Overkill i know, but thats what I do.

    1. lance_p | | #8

      Yes, their Psychologix controller is one of the coolest things about their system and makes so much sense it's crazy... what a simple concept that no one else has implemented yet! I feel like the first high performance mini-split from Fujitsu or Mitsubishi to incorporate this logic would immediately dominate the hot humid southern market, and obsolete whole home dehumidifiers at the same time.

      Also, the variable loop temperature while heating seems to be spot-on as well, only being as hot as needed to do the job. Add in their new V18 backup heating system and it's a pretty rock-solid looking package. Just one with no feedback from existing users.

      Guinea Pig is the right word; I feel the same way, unfortunately.

  5. breaton | | #9

    We recently moved into our new house with mini split heating and cooling. Aesthetics were a concern with the heads, but after “value engineering” we ended up with a fairly standard setup. Our upstairs unit is poorly located in the stairway for aesthetics. I can tell you from first hand experience that once you’re moved into your new home for a while, your wife will care a lot more if your heating and cooling system works properly and is serviceable when it breaks than what it looks like on the wall. We don’t even notice the head in our combined lr/dining/kitchen now, but she just asked me seconds ago about running the upstairs unit.

  6. JesseTrinque | | #10

    Got a reponse from Hotspot energy (chiltrix), I still have not been contacted by spacepak which is similar to the experience I had back last year with spacepak when I started looking into these units. My question is, what is that bottom temp scale I'm looking at? That seems strange to me. I would expect maybe a -10deg F to 65 deg F scale, not that oscillating one shown. I've attached screenshots of 2 of the graphs he's sent me, they are small and barely readable which is how i received them. I would assume that these COP's do not account for moving the water for distribution around the structure. This sure does seem like it would play nicely with replacing my planned AC equipment and supplementing my boiler during swing seasons and a good portion of the load during winter.

    By the way this is a Manual J i did myself on Coolcalc, anyone have any comments on the accuracy. I spent alot of time going room by room making sure the data was correct, however in almost all cases I was not able to enter nearly as much insulation as I actually have, the system was just not set up for it.

    John's response:

    "OK, perfect, thanks. Looks like a couple ways to do it using either 1 or 3 CX34 units. If doing the garage, seems like 2x CX34 is the best option. Without the garage, seems good with 1x CX34.
    Cooling/86F design 27,597 btu
    Heating/9F design
    w/ garage/basement 50,838 btu
    without garage/basement 36322 btu
    1x CX34 unit is fine for your cooling.
    I ran the heating both ways, and with 1x and 2x CX34 units.
    About reading these charts showing estimated values:
    The vertical lines – maroon is compressor provided heating
    Vertical blue is load
    Vertical green is backup heat.
    The line going across the chart left to right is COP of compressor provided heat.
    Where the COP lines diverge -top line is compressor COP, bottom line is average COP including backup heat
    Temp scale is across the bottom
    COP scale is down the right side
    BTU scale is down the left side
    About your winter temperatures, from the charts you can see where backup heat starts and what the COP is at each temp. "

    Anyone care to comment?

    1. lance_p | | #11

      Blue lines show increasing load of the house and garage with decreasing temperature (lines get longer the farther left you go, indicating higher heat load as temp drops). Based on max load of 50k BTU @ design temp, I'm going to guess the leftmost line is at 9F. Can't read the values though.

      Burgundy lines show heat provided by compressor. As the load increases with lower temperatures, more heat is provided by the chiller to match the load. BUT, as temperature drops so does the chiller's maximum heating capacity. Where the load and chiller capacity meet is called the Balance Point.

      At temperatures below the Balance Point the heat output of the chiller drops but the load continues to increase, so auxiliary heat is required to meet the load. This is shown by the green lines that begin in line with the Balance Point and grow as the temperature drops.

      These graphs just show the difference in auxiliary heat needed with your house served by either one or two chiller units, and what the overall COP is for both scenarios.

      I think he has the COP wrong though. In his graph the overall COP (chiller + auxiliary heat, yellow line) INCREASES with auxiliary heat input, but in reality it DECREASES because the auxiliary heater only has a COP of 1.0.

    2. Expert Member
      Dana Dorsett | | #12

      A heat load of 36K BTU/hr @ +9F for a 2500' high-R house is 14.4 BTU/hr per square foot, a ratio that is really QUITE high for the house described, unless there is quite a lot of window area and a ridiculous number of bump outs, corners etc (not likely if built with SIPs.)

      A reasonably tight 2x4/R13 house with R30 in the attic and U-0.35-ish windows and an insulated foundation usually comes in around 15 BTU/hr per square foot @ 0F. Your wall losses are half that of a typical 2x4/R13 house, and the air tightness should be higher to boot.

      I would have expected a 4.5" polyurethane SIP house with slightly better than code windows to come in at about 10BTU per hour per square foot @ 0F, and in the 8-9 BTU/hr per square foot range at +9F. That's under 25K for the whole-house load, but probably still over 20K. With the 24/7 plug loads (refrigerators, DVRs, etc) and warm bodies factored in it could easily come in under 20K @ 9F. It's a guess, but not a WAG.

      High performance house specs don't really fit into freebie load calculator options. Run an I=B=R type load calc on a spreadsheet using your known U-factors with a presumption of zero air leakage/ventilation. Better yet, hire a competent third party to run the numbers for you. Even if it costs you a grand (probably won't), it can save you more than that in up front equipment costs.

      1. JesseTrinque | | #14

        Thanks Dana, any recommendations for someone in my area that would be willing to perform such a calculation? So far mechanical contractors seem more interested in a calculation similar to the one I already performed, and probably with less diligence than I used. And as you said, it was hard to input the R-values high enough that support the type of insulating we did. For instance we have 3.5" of CC under both garage and basement slabs, the uniquely insulated foundation and 9+" of panelized CC foam on the cathedral roof - two layers of 'reclaimed' metal skinned sips with offset seams, one layer of 3.5 and one 5.5. I have a good source of free supermarket coolers that have made their way onto my timber framed roof. In the garage I did the same 3.5" sips screwed from up under the trusses with 12" of loose fill cellulose blown over that. The attic is 7" of CC SPF encapsulating the members of the trusses, and 3.5" of CC around all the rims. I know for a fact that these software tools are not taking these types of details into consideration. The house tested at just below 1.0ACH50 prior to sheetrock with all windows and doors installed, and that was with a massive leak under two seperate doors that I have since fixed. Our achilles heel is our windows/doors are not the best - all andersen 200 and 400. These were all new in box mis-orders and overstock that I was able to source for next to nothing. However most windows/doors are located under massive overhangs. see attached pic. Any recommendations are appreciated (though maybe not followed, I usually tend to do my own unique thing, and most people think I'm crazy... lol), I've read many of your comments throughout threads and respect your opinion based off what I have read.

        1. JesseTrinque | | #16

          Just read your response again. Can you recommend an I=B=R spreadsheet?

  7. AlexPoi | | #13

    Nordic (Canadian heat pump manufacturer) also offers an air to water heat pump. You may want to check it. This is what I'm going to put in my next house.

    1. JesseTrinque | | #15

      I just sent a inquiry, thanks! What made you go with that choice?

  8. Pantera | | #17

    I’m a little late to this post, but I’ve been using the CX34 since September and am very happy with the way it’s been performing.

    1. KeithH | | #18


      Tell us more! What climate zone? What's your design load and temperatures heating and cooling? Is it also generating your DHW?

    2. lance_p | | #19

      I second Keith's comments! Looking forward to hearing all about your CX34 installation.

    3. cr0ntab | | #20

      Photos would be great too! :)

  9. Pantera | | #21

    I’m in Reno, NV. I haven’t hooked it up to do DHW, but would like to in the future. It’s heating about 3,000 SF of space and intend to see how it will do in radiant cooling mode in the summer. My house is pretty standard 6” studs with 1” foam under the stucco. System is keeping up very well. Will likely add electric backup some time in the near future as it doesn’t quite keep up when the temp drops into the teens at night. Very easy to hook up. My dad and I did it in a weekend. I’m using their 19 gal tank as a buffer between the chiltrex pump and my radiant recirc pump. This is my first house with radiant and we love it. My goal is to install solar and battery backup. This along with my electric car will allow my to eliminate my dependance on fossil fuel. I’ll try to get some pictures uploaded. Overall, very happy with this heat pump. Plan on adding another one to a shop I have in my backyard and replace the electric water heater I am currently using on the radiant in that building. I’m a little concerned about long term reliability and parts availability, but couldn’t find anything else on the market that match the performance and price.

    1. JesseTrinque | | #25

      That's awesome. I ended up going with a propane boiler... I just could not accept the risk I guess. I really wanted to go with the chiltrix but chickened out at the last second and caved to everyone around me telling me it was a risky idea. I'd love to hear more and what your install looks like...

  10. Deleted | | #22


  11. Deleted | | #23


  12. samueldnewman | | #24

    Hi all, I'm posting here so I can see responses. I've been researching the Sanden SanCO2 unit, but am only just now learning about the Chilltrix. I'm curious about electric hydronic heat in Climate Zone 6A (Vermont).

  13. LauraDianeS | | #26

    Weighing in on Chiltrix CX34 here....... after much research, I chose this system for my 1300 sq.ft. passive solar, hydronic heated home in Zone 4 (northeast Oregon) My electrician/and plumber had no experience with this system but said the specs were impressive. I have had nothing but problems, since day 1. This is now my 2nd winter using this system and I am about to rip the whole thing out and ask for my money back!!! BUYER BEWARE!!! Tech Support has been very patient and responsive, though the "errors" persist. I am afraid if I go to the company (is it Hotspot Energy or Chiltrix I would contact?) they will say it was an install issue. I recently came home from a 2 week trip, and while I was gone, an element in the buffer tank overheated, melted the discharge pipe and sprayed 80 gallons of stinky, oil glycol all over my garage!!! I am about to file an insurance claim for all the damage but wanted to ask you guys -- what would you do in my situation?? A brand new home should NOT be having these issues and I just want my money back, and have another system put in (recommendations anyone?) Do I hire a lawyer? Contact Chiltrix? Contact the Better Business Bureau? My insurance said the claim probably wouldn't pay for a new system. I WOULD DEFINITELY NOT RECOMMEND CHILTRIX!!!!

    1. lance_p | | #27

      L D, wow, what a mess! Can you elaborate on the Errors? Are these error codes on the CX34 unit or something else? What are the errors for (what is going wrong)?

      Not sure what to say about the buffer tank. Almost sounds like some safety system didn't do its job... traditional water tanks have a T&P (Temperature and Pressure) valve intended to allow the tank contents a predictable path to a floor drain should something go wrong.

      1. LauraDianeS | | #31

        Since day 1, I have been getting error codes on the CX34 wall mounted "controller unit" - mostly P5 and P14. In/Out water temp too low
        One thing I did not consider when purchasing this unit, was the lack of qualified installers and maintenance people in my area. I live in a VERY rural area, with few subcontractors to call on.
        I've spent my life savings building the home of my dreams, a home I never wanted to have to "fix" anything (well, at least not a brand new heat pump!) and this was a bad heating-system decision on my part. The discharge pipe does not go to a floor drain, but is very close to the overhead garage door, so maybe the plumber thought a routing to a drain unnecessary. Should I ask him? My garage does not have a drain.
        About 2 weeks ago, Chiltrix Tech Support sent me a little module-thingy that I plugged in to a laptop and my heat pump to download/install a "fix" that would eliminate the P14 error. Still getting the error...... Shouldn't Chiltrix or Hotspot Energy be responsible for fixing this, and paying for all the damage in my garage from the boiling glycol spraying on everything? Who should I call?

        1. polyakov | | #61

          P5 error is exactly what it says in the manual... indoor unit water flow error. Check C13 parameter on the controllers display and make sure you have correct flow in l/m. I had air bubble in the pipe that blocked the water from flowing and got this error yesterday. I had to purge / re-fill each fan coil separately to remove air and was back up in no time. To correctly purge your system of air I advise to have 2 accessible ball valves per fan coil (for in/out) so you purge one circuit at a time.

    2. Trevor_Lambert | | #29

      You have to contact Chiltrix and the installers, and allow them the opportunity to make things right. If you contact a lawyer first, that erases any potential of good will on their part. If it goes to court, and it comes out that you didn't give them a reasonable opportunity to resolve the matter, it will look bad on you.

      Don't waste your time with the BBB. They somehow have a public perception as some kind of dispute resolution body, but it's not true. They have zero power to make a business take any action, and they have zero motivation to even try. Their complaint process works like this: you complain, they record it and send it to the business; business responds, case is closed; business maintains A+ rating by responding to all complaints. Note that it does not matter what their response is, only that they respond in some manner. In other words, if they decide to just say "customer is wrong", that is the end of that.

  14. KeithH | | #28

    Wow! Yeah, what happened with T&P valve? And why was the tank element working so hard?

    You definitely should try for resolution with chiltrix. And I'm guessing several of us are curious to hear how that goes?

  15. Jon_R | | #30

    > an element in the buffer tank overheated

    Is this using a Chiltrix tank heat controller? With just a quick look, I don't see that they even sell one (all I see are bare tanks).

    P5 and P14 means low flow (or much less likely a switch failure). Sounds like an installer error.

    No doubt that hydronic systems (even without heat pumps) are more complex and should be installed by experienced installers.

    If this is purely an installer issue, then you shouldn't be blaming Chiltrix at all.

    1. LauraDianeS | | #32

      yes, it is. all components came from the factory

    2. Expert Member
      Akos | | #33

      Here is my guess.

      There was something wrong with the install and the outdoor unit was not making enough heat (thus the constant low temp errors).

      The backup elements in the tank were not wired up properly or somebody tried to rig it so both elements can operate at the same time to get extra heat.

      Eventually the tank thermostat gave out (which is extremely unlikely with a properly wired tank with dual T stats) leaving the elements full tilt. Tank overheated and vented as designed. Since the vent was not run to the ground (as it should be) it made a mess.

      To troubleshoot, first try to figure out if the outdoor unit is making enough heat and check the wiring on the buffer tank.

    3. LauraDianeS | | #34

      I don't know who to blame. I just don't want any more problems. I don't know if my plumber or electrician (who have been on speed dial with Chiltrix tech support this whole time) are qualified installers. They have installed many hydronic systems, but never with Chiltrix. They never acted like or said they were having any problems with the install. This is a touchy issue, though.... with me being a woman, living in a small, rural town. I don't know if these subs are being straight with me or just trying to cover their butts and reputations. They certainly haven't copped to it being any of their doings. This is costing me a small fortune...... not to mention the stress and anxiety of my heat going out in the dead of winter.
      Oh, and I just filed an insurance claim for all the damage in my garage from the spewing glycol..... my insurance agent is the wife of my electrician (small town life!)

      1. JesseTrinque | | #36

        Your story is the exact future scenario I was scared would play out for me and the reason I opted against the Chiltrix and instead went with a condensing gas boiler. I LOVED the idea of the system but was too scared to take the plunge. So far happy with our system and the propane bills have been more than reasonable. House is basically double the size of our former early 90's cape and propane bills are about a 3rd less in the new house than the oil boiler system in our old house.

        For whatever it is worth, in all the dealings I had with Hotspot energy they seemed to be very sincere and good people. I would recommend making a call directly to them (not through your subcontractors) and see what they say. I believe I talked to Jon there and he was very forthright and seemed genuinely ready to help any way he could. Maybe it is an installation issue that they can help troubleshoot with another contractor.

        1. lance_p | | #37

          Jesse, I recently found a local homeowner who had a Chiltrix CX34 system installed in his Passive House. I spoke with him on the phone to gather some information about his installation. He indicated that they had a few initial setup hiccups to work through, but that he got exceptional service from the team at Chiltrix and reinforced that they went over and above to make sure that everything was in order. He's a handy guy but had absolutely no experience with these systems prior to having this installed.

          L D, I agree that your first call should be with Chiltrix. Hopefully they are able to figure out what went wrong and how to make it right. Please let us know how this all works out, good or bad. Hopefully it doesn't end up in a game of finger pointing. Best of luck!

  16. Jon_R | | #35

    > I don't know who to blame

    Yet you seem to blame Chiltrix.

    But I'm not unsympathetic. I'd bring in an installer with some Chiltrix experience. If that's not very feasible, then I'd document everything really well and try using an experienced Chiltrix installer remotely. Pictures and schematics posted here might catch some issues.

    1. LauraDianeS | | #38

      Excellent idea, know of any Chiltrix installers? I have documented everything since day 1, every error reset, etc. The part I don't know, is what the installers did/did not do, because they don't tell me everything (not that I would know what they are talking about!).
      My subs have been working with Mark (Hotspot Energy tech support) all the time and checking everything out, errors still persist, now in my 2nd winter.

      Thanks everyone for your responses and help, I really appreciate it!!!!

      1. KeithH | | #39


        How did your tank disaster turn out? Is your unit working? Did Chiltrix take care of you? What was the problem?

  17. Fourthbean | | #40

    I purchased a CX-34 unit and some indoor units spring of 2018. Now that they have been installed for about a year I've started documenting some of my experiences. In my case this is a retrofit as the existing forced air ductwork in the crawlspace had rusted through, I figured something like this would end up costing less than having all that ductwork replaced/patched/sealed. I still have some indoor units to install as we are running in about 2000sqft right now with the other ~900 closed off. I am generally happy with the setup. Something I'm wary of is the defrost cycle. It's on a timer not a sensor which seems inefficient for a unit that has a claim to fame of being a high "seer" rating. If anyone has specific questions I might be able to help with feel free to shoot them my way, whether as a comment on one of my videos or here. I'll do my best to answer.

    General explanation of how I installed my system:

    A look at one of the FCU's:

    Playlist where I will add any additional videos I make on the Chiltrix:

    1. lance_p | | #41

      Many questions! Let's start with:

      1. What is the info for your application? Loads, design temps, climate zone, house size, blower door score etc.
      2. Are you using any electric resistance backup? Baseboard heaters, or perhaps their new V18 heater?

      And finally, you say you're using valves to shut off water flow to individual FCU's (coils). Did you come up with this design? What benefit does it serve? I'm just trying to figure out why you would require the level of troubleshooting and working-around you seem to be doing to get it to work.

      You may even consider starting your own conversation here as this one has taken a few tangents. If you do, please post a link to it here so it will be easy for all to find.

  18. Fourthbean | | #42

    Lance, you might be disappointed in my response. This was a retrofit and I did it all myself. I did run a rough Manual J and played with the BTU rating of each FCU and came up with about 4 tons of cooling needs inside the house. Downstairs anyway where this unit would be installed.

    We are in climate zone 3 here, so I was mostly concerned with its cooling and de humidification performance.

    I didn't install any backup heat. Over the winter we did drop into the teens a couple nights in a row, it did struggle to keep things warm when it was trying to defrost itself so often.

    As for the valves. My idea spawned when I was reading the manual and saw you could affix an electronic valve to the FCU. I figured if water was flowing through that coil only when it was needed I'd be that much more efficient. Really what I was trying to avoid was the loss of cooling/heating in the lines under the house that led to each FCU that wasn't in use. We have 2900sqft of space and I suspect half of that will be unused most of the time so we could just not heat/cool that space.

    As for it not working flawlessly, I talked to Chiltrix support about this. They mentioned having a valve on each FCU wasn't really the idea. They envisioned someone putting a valve on a subset of the FCU's but not all of them. So the complication was my own doing, with a little help from the Chiltrix manual :).

    Yes I'll have to get my own thoughts on the system a little more organized and make another post. Did you end up making a decision for your place or are you still in the process of building?

    I'm attaching a diagram of how I laid out my system logically.


    1. lance_p | | #43

      I'll take any information about the Chitrix that I can get my hands on. I'm about to apply for our permit and the application will include a tiny gas furnace (30k BTU) with a heat pump air conditioner, a really neat dual fuel system from Dettson, a Quebec company. Whether or not I end up going through with that system or not will depend on whether I get comfortable with the Chiltrix between now and the fall when I need to install a heating system.

      So your valve setup was an attempt at "zoning" the system the way Chiltrix intended, just a more extreme and harder to control approach. Got it. I was thinking along the same lines, only adding heat to the North side of the main floor on sunny winter days for example. Sounds like a more traditional approach to zoning is OK with them.

      2900 sqft and 4 tons of AC? That sounds like a lot. How did the 2 ton CX34 do?

      Our heating design temp here is -15F (-26C, Ottawa Ontario, CZ6A) and my rough load calculation including the basement is between 21-25k BTU depending on final infiltration values. Trouble is, the CX34 is only rated down to -4F so I'd be using the backup heat quite a bit. Even at -4F I'd need about 4k BTU/Hr from backup heat based on their rated heat specs.

      I haven't talked to the company yet to get their recommendations, we'll see what they have to say. If the unit will produce some heat at -15F and they recommend a second unit, well, that might put the equipment cost over the top. Even just with one CX34 I'm looking at over US$9k by the time I put a FCU in each bedroom, two on the main floor and one in the basement. Not cheap.

  19. Fourthbean | | #44

    Here in the big D our hearing design temp is 26 F and cooling is 99. As a reference most typical homes around here have a ton of cooling per 500sqft. I’m sure the brand new ones are getting better than that slowly but surely.

    2 tons did fine over last summer. We were only cooling about 1500sqft of it though. The house is a work in progress so the front rooms are still under construction.

    That’s a fantastically low amount of heat you will need. Our last house here in Texas had a 50kbtu gas heater for 2100sqft... in its defense it was built in ‘69. There’s definitely an advantage to building new over trying to seal up an old house like I’m doing.

    It does get expensive quick adding fcu’s. Curious though, have you been able to determine the cost difference of plumbing for a chiltrix unit over ductwork? I assumed ductwork would be more expensive in my case but it might be different for new construction.

  20. jchaters | | #45

    The Chiltrix unit has not been in North America very long, does not have an established service network, is made in China and tells a great if not unbelievable efficiency story. I work with Aermec, we have been in North America for 12 years, have a "smart defrost" not a typical time BS defrost and have established service and installing contractors. Buyers beware. Jim

    1. cr0ntab | | #46

      I took a look at the Aermec units and they remind me a lot of the SpacePak Hydronics units. While I would agree that these two options are probably more stout than the Chiltrix units, I still think the Chiltrix wins on efficiency.

      The Chiltrix unit is a DC inverter drive for the compressor, I believe (and please correct me if I'm wrong) that the SpacePak and the Aermec are not DC inverter driven compressors.

      I believe these two units use traditional on/off compressors.

      From this page:

      Looking at your presentation ( on slide 65 I see mention of a soft starter.

      DC Inverter driven compressors (much like the ones found in mini split systems) don't require this component. I've only ever seen this component used on traditional on/off compressors. (Again please correct me if I'm wrong here)

      I liken the Aermec/SpacePak units to a traditional AC condenser, The SpacePak could even be considered a two stage condenser.

      Where the Chiltrix would be more similar to a mini split condenser.

      The ability to modulate the compressor motor up/down is where a lot of energy savings is derived from if I'm not mistaken.

      Definitely not bashing the product, it looks very stout (and even more expensive than the Chiltrix).

      1. jchaters | | #94

        Made in Italy not China. We will be bringing our inverter this fall but in reality the difference in efficiency is very little. A standard scroll into a buffer tank operates at a great efficiency and then shuts off until the tank is drained. The inverter modulates allowing for a smaller buffer tank. Efficiency almost a wash.

    2. lance_p | | #47

      Jim, I wonder how many people were saying the same things about Aermec 10 years ago?

      Also, page 14 from the presentation linked to by Robert shows heating COP of 13.30. Who's telling the unbelievable efficiency story now? Professionals will understand that Aermec is not reporting COP as W/W like everyone else does, but Joe average might look at that and think he's discovered something special. Perhaps that's the goal of this document?

      To be fair, I know nothing about Aermec products and they could be the best thing on the market. However, for a company rep to start posting negative (and purely speculative) information about a competitor's product in a public forum certainly doesn't look good on Aermec.

      Chiltrix claim to have their CX34 heat pump AHRI certified with the following data:

      System - IPLV/NPLV Test Conditions - Capacity BTU - IPLV/NPLV COP - IPLV/NPLV EER
      CX34 - Cooling at A95°/W55º - 30,049 - 9.0 - 30.72
      CX34 - Cooling at A95°/W44º - 26,150 - 6.75 - 23.02
      CX34 - Heating W95º/A47ºdb/43ºwb - 33,813 - 3.92 - NA

  21. jchaters | | #48

    Actually I am only negative because I have seen at least 6 Chinese units come and go in the last 6 years leaving people stranded. I would hate to see it happen again, the biggest problem with Chines units is their lack of proper defrost, they eventually destroy them selves. How many Unico ( mad in China units) have failed, last I heard 3000 and there are two units being sold in North America right now from the same factory. I hope they work for you. Jim

    1. lance_p | | #49

      "Chinese" is an awfully broad brush to be painting products with. I'm all for domestic manufacturing, but heck, the time to save it was 50 years ago. It's a small global world we now live in, like it or not, and crappy products are just as likely to come from domestic sources as they are from overseas anymore. The company dictates quality control, design and product reliability, not the country of origin.

      I'm curious (and somewhat naive) about proper defrost strategies, and I'm in Canada where defrosting a heat pump is important. Can you elaborate on the differences between different approaches? Perhaps I can arm myself with some good pointers.

  22. jchaters | | #50

    Well in Europe heatpumps are tested with defrost and it is actually an efficiency penalty so they must develop smart or efficient defrosts. It seems certain countries that manufacture these units use a timed defrost. The unit goes into defrost below a certain temperature weather it needs to or not. I am not picking on a particular country, it is just that this country is putting out air to water heatpumps that fail consistently. I have attached a document on Aermec defrost or "smart defrost" it may read a little off with multile circuits and fans as it was written for our larger units (upto 250 tons) but it is the same on our single circuit residential machines. We also developed a drain pan heater for Northern climates to get rid of all the ice when we have large defrost periods and then the temperature drops and forms ice in the base. Without a drain pan heater the ice will crust the copper coils another major problem. Wish you well, Jim

    1. lance_p | | #51

      Thanks Jim.

  23. user-7416797 | | #52

    My company just pulled a Chiltrix CX34 system out of a new home construction. Had installation problems with wrong fittings shipped and parts availability. Technical support person was good but it ultimately came down to system performance. The Chiltrix unit display panels show fluid flow and fluid temps going in to the CX34 units and coming out. I just cannot see that the units perform in accordance with specifications. We set the operating parameters exactly as Chiltrix instructed. Yet when we did not get the heat expected for the outside ambient temperature, we were told we did not have the controller properly set. We also had condensation problems with the fan coil units mounted in a horizontal position. Very expensive lesson learned.

    1. lance_p | | #54

      Would you mind elaborating on the heating issue? I.E. what outside conditions, what indoor conditions, and what size Fan Coil Units? If you were in heating mode, how come you were having condensation issues with the indoor FCUs? Was this related to the outdoor unit defrosting?

  24. KeithH | | #53

    What did you replace it with?

  25. KeithH | | #55

    Hmm, kind of a driveby complaint I guess. Maybe they will give more information over the weekend? I'm guessing several of us would love answers to the questions I pose below (highlighted with ***)

    Here's my concern with this post, which so far isn't answered:
    If they plumbed the chiltrix as the manufacturer specifies, then they installed wild supply and return loops (I believe that is the term). I'm not aware of another piece of equipment that operates this way (anyone else know of one?). So what was the replacement.

    Most hydronic systems are primary-secondary right? (at least in a multiple zone system) I think a lot of hydronic professionals like to install primary-secondary (I'm not a hydronic pro!). As I understand it, the chiltrix does not support or work well with primary-secondary.

    So here's why I asked what they replaced the chiltrix with:
    - If you installed a non-spec'd distribution tubing, then we really don't know anymore about the chiltrix than that it doesn't work if you install the tubing not to spec (ie try to use with primary-secondary). That's helpful but only if you tell us that's the problem. Not a retrofit option for primary-secondary: check.
    - if they installed it non-spec (primary-secondary), then they probably had some choices for replacement (if heat only, a boiler; if heating and cooling, arctic supports primary-secondary I believe; maybe other air to water units?). What did you replace it with?
    - if they did install it to wild loop spec, then what system did they replace it with and how did they retrofit the layout to primary-secondary? Surely they didn't rip the wild loop out of the finished structure? Surely they didn't install the FCUs in an only roughed structure where a revision was still possible? I can imagine a scenario where the wild loop would be adequately exposed (1 story, unfinished basement or crawlspace with exposed 1" pex wild loop) but if that's the case, let's hear about what structure and layout allowed conversion from wild loop to another system. I know I wonder what you do if the chiltrix doesn't perform because of it's piping requirements, especially if the piping isn't exposed. The solution would be valuable knowledge.

    But I'd also like to know how badly it was performing. If you had to rip out the distribution piping in a finished structure, surely adding a second compressor to the chiltrix to achieve higher BTU output would have been more sensible. Did you try increasing the loop length? Adding a buffer tank? Was it plumbed to provide DHW? Did you try eliminating DHW production (the most easily replaced part of the system I'd guess)? Did you insulate the pipe to spec? It's a pretty technical system that isn't very familiar from an ordinary hydronic system perspective. More information about your problems and attempted solutions.

    Here are my questions in condensed list:
    *** What was the original piping layout?
    *** Was the chiltrix providing heating only, heating and cooling, or DHW as well? (or DHW only)
    *** What system did you replace it with?
    *** If the distribution was wild loop, how did you address the unusual layout with the new system (or why did it not matter)?
    *** You say: " I just cannot see that the units perform in accordance with specifications." So in terms of performance, does that mean it didn't produce adequate BTUS or used too much wattage? Or ??
    *** You say: "We also had condensation problems with the fan coil units mounted in a horizontal position." I assume this means ceiling mounted and that the condensation dripped from the unit rather than being collected. Presumably this means you were using the units to cool... Were you using the special controller they offer (Psychrologix)? Was the building fully dried from new construction or was this new construction? What were the ambient conditions (WB/DB/RH, controller settings).

    That's not meant to be inquisitional. Just asking the questions that those of evaluating the system likely have. Is it really junk (that seems to be your final assessment or you wouldn't have ripped it out) or situation more nuanced?

  26. lance_p | | #56

    Excellent questions, Keith! Inquiring minds would like to know!

  27. jchaters | | #57

    Primary secondary is most popular yes but I have seen many single loop systems with zones and they work as long as the zones have 3 way valve to stop the from dead heading. The biggest problem I have seen with air to water installs is lack of water volume or low flow. The second biggest failure is poor defrost controls from the manufacturer which eventually blows the machines up.

  28. BrianRJH | | #58

    Fourthbean had to put in a condensate overflow switch, or he chose to put one in.
    At my job I put " slime tabs" in the condensate pans to hopefully prevent clogs.

    1. Expert Member
      Dana Dorsett | | #59

      He didn't test the float switch with a cup of water, which might have been important to prove out given the odd angle at which the float switch was installed.

  29. BrianRJH | | #60

    True, he had to force it in there. I think regular maintenance will keep one ahead of most drain clogs.

  30. golden2husky | | #62

    I have installed a Chiltrix CX34 system on the first floor of my house last August. Second floor has a traditional central A/C system, albeit one with serious insulation (2" polystyrene covering over the fiberglass sheet). Like the second floor, I did the installation myself, but had a mechanical engineer size out everything. I'm an EE, not a ME. I live on Long Island NY and the plan was to use the Chiltrix for A/C and shoulder-season heating. The primary reason for going Chitrix is that we own a historic home and maintaining the appropriate look was the highest priority, with energy efficiency a tight second. This was not a job for the inexperienced; my project required carpentry, plumbing, and electrical skills. NP here as I have all of that covered. If you are not strong in these areas, I'd suggest a contractor. Oh, and plenty of money for materials.

    I installed one (1) two ton heat pump and five fan coils. The collective tonnage of the FCUs is 15% more than the two ton rating. I did not buy the special controller for humidity. I piped from the outside with brass fittings to copper tubing (1") for 90% of the system; the remainder was 1" PEX. Why not all PEX? In the basement I wanted all the piping to be straight and when you sight down the line of piping, I had to have everything be parallel and look perfect. If that is not important, I'd suggest all PEX. Much easier and WAY cheaper. I used rigid 1" fiberglass insulation with preformed fitting covers and PVC covers on everything. I used a reverse return and isolation valves on every FCU. Good move - more on that later. All the piping is supported with proper hangers and I made support saddles for each hanger location. The goal was to mimic the look you would see in a well made commercial building. All of this was a success.

    On the first floor, each fan coil was built into the structure of the house. When renovating the kitchen, I left space for a horizontal FCU and the piping. Two others are built into the wall. All will be integrated when renovations are finished. The finished ones are not visible. All you see are custom-made grilles that look like the late 1800s. Again, mission accomplished.

    Now, the functionality. The system does work very well. It handled the heating load in the fall very well, but with our high electric rates, the cost of energy was a was a wash compared to running the grossly oversized gas boiler (will be replacing in future but no way would I ever get rid of the cast iron radiators). So, I probably keep heating as a backup to the boiler. Cooling performance is very good, quiet, and unobtrusive. So, a lot to like.

    Now, the negatives. One, I feel this unit is over-controlled and loves to toss trouble codes. I was getting the P5 low flow code so I contacted Chiltrix. I have to say the support was excellent. The guy (Mark I think) walked me through everything and explained a host of parameters and was able to predict what the numbers would be and what they would change to. Ultimatly the unit needed the second pump. Flow problems solved. Next up is the wild coils. The problem with wild coils is that when you have very little load, the FCU can overcool the area. The fan never is really off - makes sense as you need to get an temperature sample from the room into the FCU. Not that big a deal but my wife's Amazon parrot did not appreciate the 62 degree temp one morning. A location like this would be best served by using the three way valve to fully kill the flow. So, a solvable problem. The other issue is the FCU manual sucks. It clearly says not to "insult the pipes". It also did not mention that for horizontal installations, you need to remove a section of weatherstripping to allow the condensate out. This caused me to have to access the unit that was pretty deeply built into the wall. Mark had the answer here as well, but I had to redo a bunch of construction work. I don't like redoing work. A word of caution also regarding the insulated the basement they sweat! Even with a full inch of quality insulation. I did not want to use a dehumidifier, but with a level of 80% down there I had no choice. Sweating went away after the RH was down below 50%.

    Now for the biggest concern. I just went offline this morning with a P13 - inverter communication or inverter fault. I am near the end of the warranty period....calling this morning to see what happens....I'll post response. I can post some photos if anybody wants to see them...

    1. lance_p | | #63

      I would LOVE to see as much information on this system as you can post! Thanks for all the information so far. It really does seem like a great system, though as you’ve pointed out, it has some quirks.

    2. polyakov | | #64

      I also noticed that fan coils are always running and found your solution to this quite interesting.

      Can you share the model of the three way valve that you used to stop flow on the fan coils?


      By the way I also had lots of P5 errors that turned out to be air bubbles in pipes. Also, I live in NYC and use CX34 for AC/DHW and heating in the winter, I.e. I completely switched to this unit for all of my house needs.

  31. Matt_N | | #65

    A new passive house build in Wasaga Beach, Ontario, Canada is using the CX34 for heating, cooling, and DHW. The system was engineered by a third party company, so it will be interesting to get the owner's feedback once the house is finished.

    1. polyakov | | #69

      Regarding two or three way valve for the fan coils.. after reading up some documentation on the fan coils I found out that you can simply configure the target cooling temperature in the settings (parameters 03, 05 and 20) and the fan coil shuts down the fan when it gets too cold in the room and wakes up every 15 minutes to check the room temp. So looks like a closing valve for fan coils is not necessary.

  32. golden2husky | | #66

    I called Mark at Chiltrix and he suggested testing the fuse for the inverter board located on the top of the unit. He asked if I had a DVM to check the fuse so I did so. Sadly, the fuse is soldered to the board; I guess a proper holder was "value engineered" out of the final design. I snipped one end and tested it. Sure enough it was blown. We did have a power failure - my backup generator is offline at the moment - so it is possible that was the cause. He is sending a few replacements to me but I have to solder it to the board myself. I'm cool with it but I suspect the vast majority of customers would not be for a unit under warranty. If I have to solder anyway I will install the holder that allows for easy fuse replacement.

    As for the question about the three way valve, Honeywell makes a few 3/4" models that would suffice. I have not installed one as of yet because we just got into the habit of hitting the power button on that particular FCU when we suspect it will be necessary.

    Regarding air trapped in the system, I sprung for the air eliminator that Chiltrix suggested. Not cheap at over $300, but it purged the air beautifully. One thing about this system is that the materials are very costly. The equipment from Chiltrix was almost $8,000 delivered. I spent another $3,000 on piping, fittings, insulation, and the custom grilles. Electrical and concrete pad was about $350. All labor was on me, and the sizing design was done by a friend. If I was a typical homeowner and had to pay a contractor for the same quality install, I'm sure I would be looking at $20K, excluding the carpentry to hide the units. I don't really expect to see too many of these systems because of cost. Even going all PEX would still likely run about $15K.

    I'll post a response after the fuse arrives....and maybe do a comparison to last year's electrical consumption. This unit offsets a large window unit that droned for many a summer...

  33. golden2husky | | #67

    Update - Chiltrix agreed to send me a new inverter board instead of me having to solder the new fuse in. I had tried alligator clips and the same size fuse and the unit still did not work. I borrowed the inverter from some CX34s in stock at work and put it in my chiller. Success! A/C restored. Mark was gracious enough to agree to send a new board right away. I will put that back in the work unit and I will mail back the bad inverter. Not really sure what took this out. There seems to be a pretty good amount of TVSS components on the boards but...

    Ultimately Chiltrix stepped up with support and was willing to send the new board out before the old one arrived. So I still give this unit a recommend suggestion if the traditional mini splits are not for you.

    1. lance_p | | #68

      Cost of the equipment is a significant factor. Added to the lack of coverage and reviews, I chose to go with a more conventional approach. Great to hear they have a good support system though.

      Message to Chiltrix: Get on board with some green builders and PROMOTE YOUR PRODUCT. Get some units out there in the hands of builders with YouTube channels and let them run with it. You've got an impressive looking system that few people seem to know anything about, and fewer still muster up the courage to take the plunge.

      I'm really bummed out that I've decided to go the safe route with a gas furnace. I wanted to do something cool and different, and going all electric would have been awesome. Minisplits won't work for me (wife hates the wall unit look) and ducted heat pumps are lower efficiency and way more expensive.

      I contacted you about the system and you put me in touch with my local Hotspot dealer (Ottawa Ontario); they had never sold a single one of your heat pumps and didn't even have pricing on your newest gear. In fact, when I asked them about the CX34 heat pump they gave me pricing for the CXI34 fan unit instead... they'd never heard of the CX34.

      I hope you're able to capitalize on your unique and innovative ideas before the rest of the industry copies them.

  34. Twosistersproperties | | #70

    My name is Judy Hartzell. 3 years ago I took the unfortunate green path with Chiltrix. Not just one until but my entire apartment building. 6 units.
    First mistake no local contractor understood them. I chose one and he put the entire system in wrong. I have invested over $100,000 into these units and Chilltrix refuses to come
    from Chesapeake to Michigan to define what is wrong so I can either get it corrected or sue the contractor. Now you heard me say 3 years. It’s a nightmare. I’d appreciate any info anyone has that I could use to solve this matter. Thanks Judy

    1. Jon_R | | #71

      Few manufacturers would send people out to work/report on an installation done by a reseller. So it's not clear that Chiltrix has done anything wrong or that there is anything wrong with their product.

      1. jchaters | | #93

        Well I have sent local trained contractors out at my expense to solve problems that others made with our equipment so I disagree.

    2. jchaters | | #95

      Judy it is typically a problem with water flow or lack of water volume. If you would like I would be willing to try and help. Jim

  35. Twosistersproperties | | #72

    Weill I find your answer interesting. Do you have Chilltrix products. You are in Michigan right. If you do have them and know an installer with experience I’d really be interested in their information.
    I did not say there was a Chilltrix error however how do I know if no one who is qualified will help me
    My Husband passed away in January and he at least understood what installer did wrong. It was truly a nightmare. I rent these units to Corporation fir a hefty monthly amount and everything
    has to go perfect. My entire estate is wrapped up in this building And I’m have to use my very old costly boiler to supply heat. Paid another contractor $15,000 this summer to get two units to work suppling air. I can’t go on like this and everyone seems to point the finger at ever one else. I have had to replace the computer boards in 5 out of 6 units.

  36. Twosistersproperties | | #73

    Also I bought them myself directly from Chilltrix

  37. polyakov | | #74

    Describe the issue. Show pics, diagrams, etc.

    I use Chiltrix for heat/cold/dhw.

  38. Jon_R | | #75

    Perhaps this line from the CX34 manual hasn't been followed?

    "It is advisable to add surge suppression and transient voltage protection to the circuit powering the chiller."

    This is complex subject, but I've had noticeably better results using protection devices that a) attempt to absorb surges AND b) disconnect the load when voltage is outside of normal ranges. This is with other devices - I don't have a Chiltrix.

    1. Jon_R | | #76

      There are other important and perhaps not expected things in the CX34 manual that need to be followed. For example, "Primary Secondary Piping or Closely Spaced Tees are NOT supported". And that their fan coils are typically used with them all in parallel, with 1" pipe and reverse return - no zone valves, manifolds or balancing valves. Head loss calculations must be done correctly and a Chiltrix auxiliary pump should be used if it is too high. It's not a system for a "I don't read manuals or do math" installer. Chiltrix attempts to help with "PLEASE SEND YOUR PROPOSED FINAL DESIGN TO CHILTRIX SUPPORT DEPARTMENT FOR COMMENTS & SUGGESTIONS".

      I got a first hand report that a CX34 was still working at -22F. And works quite well overall.

  39. AlexPBrown | | #77

    I've been watching this thread and I decided to go with Chiltrix as both a replacement for existing residential Chiller (Multi-Aqua - 8 years old, sounds like a tank) and to tie-into our natural gas boiler and radiant loops (Triangle-Tube Prestige Excellence). We have done a lot to our old home to make it more sustainable - spray foam insulation, solar hot water, solar PV - a system large enough to cover our energy use for home and one of our 2 electric cars. Being able to heat with renewable energy has been appealing to me for some time, but we lacked the space in semi-urban NJ to put in a geothermal heat pump and so I've been converting to low-temp radiant heat as we renovate room by room in order to eventually be able to heat efficiently for most of the year with a heat pump.

    That day just arrived. I'm a handy guy and have done much of the renovations on my house myself, so the DIY support from Chiltrix and the fact that there is no need to handle refrigerant were critical deciding factors.

    System Characteristics:

    The Chiltrix primary loop is just between the buffer/ storage tank and the unit outside. Other pumps pull from that tank on demand. The Chiltrix just keeps the insulated tank at the required setpoint depending on it's mode of operation.

    A/C distribution:
    Our A/C plumbing is mostly insulated PEX with push-fit fittings. 1" loop visits all air handlers in house. 2 hidden in ceiling with minimal ductwork (there is no room for ductwork in our house) , and 3 high-wall units (3rd floor and basement). The distribution pump is over-engineered but efficient - Grundfos Magna in constant-pressure mode, so it uses very little energy when valves are closed on air handlers. The high-wall air handlers don't communicate with the Chiltrix, so we currently have to turn it on or off - it is always cooling the liquid in the buffer tank when on - even if no air handlers call for cool. We are working on that for Phase III.

    Heat Distribution:
    We have a higher-temp radiant manifold and a lower temp radiant manifold. The high-temp one (staple-up radiant floors and radiators) is connected to the boiler loop and the low temp one (overlay radiant floors and radiant walls) is connected to the Chiltrix buffer tank. There is a pump that mingles the boiler loop with the buffer tank, allowing either system to heat the other. The arrangement is largely a product of the evolution of the system and constraints on the renovation, I didn't set out to build something complicated. Currently, the Chiltrix is set to about a 109 degree setpoint, and the boiler is on an outdoor reset so the Chiltrix naturally takes over for the gas boiler when it's outdoor reset falls below 109.

    The support from Chiltrix was really quite good. The previous vendors (Multi-Aqua and SunMaxx Solar) that I've worked with were total crap on support, Chiltrix was a breath of fresh air. There was a period of time where the flow valve was failing and then failed and we were getting some P5 Low Flow Errors. They were able to help me diagnose the problem and sent a replacement valve - which I installed backwards - and they even figured that out in short order. They seem to be quite knowledgeable and their product has enough sensors and settings easily accessible on the display - that they are able to acquire the information they need on a tech-support call to troubleshoot. I also had issues getting the air out of that primary loop, so I build a home-made purge fill cart out of my old chiller 1/2HP pump and a bunch of PVC and was able to purge the lines.

    Future directions:
    In Phase III I will attempt to build a Modbus controller with a raspberry pi and some temperature sensors that communicates with my Triangle Tube boiler and the Chiltrix and decides when to use each for each manifold based on the COP of the Chiltrix for required setpoint and outside temperature. Additionally, it will monitor some built-in thermostats to determine when to turn on the Chiltrix for heating and/or cooling. The goal will be to find the optimal balance between cost of operation (while running from renewable energy electricity supplier) and to use as little fossil fuel as possible while maintaining a comfortable environment for my family.

    1. Jon_R | | #78

      Thanks for the report. Re heating: when you create your own controller, I encourage you to make the outdoor reset temperature adapt to actual load (vs just load inferred from outdoor temp). Normally it has to be set high to account for worse case wind conditions and this has a negative effect on HP efficiency. Done right, flow to the radiators is continuous (until load goes to zero).

      Also plumb so that the coldest water (usually the return from the radiators) goes directly to the HP (ie, doesn't get mixed into the buffer tank).

      1. AlexPBrown | | #79

        Thanks! Sage advice. I do have the cold return from the air handlers coming back that route, but not other radiant loops. I'll consider making that change.

        I was also considering adjusting the reset to load - particularly in the morning when I have to raise the temperature of the house - making a "positive correction" to the reset temperature to reflect the additional load of bringing the house up to temperature - perhaps taking the difference between internal temperature and thermostat setpoint and factoring into the reset temperature.

        Maybe that is Phase III ;)


      2. pnwbuilder | | #81

        I understand that HP works more efficiently when the temperature raise needed is higher, but doesn't running the return directly to the HP defeats the purpose of having the buffer tank?

  40. AlexPBrown | | #80

    I think New Jersey now has a $2000 rebate for the purchase of a Chiltrix, FYI. I'll post more as details develop.

    1. rhl_ | | #82

      Alex, have you had any further issues with your Chilltrix? Would you be able to post a diagram of your system layout?

      I’m considering purchasing, it would be great to ask you some questions about your experiences 1-1.

      I’m not sure how to contact you directly though..

  41. cr0ntab | | #83

    There are a few folks chatting in this group:

    1. lance_p | | #84

      I'm not on FB. Anyone care to paste some info here if relevant?

  42. user-6810945 | | #85

    Quick update on my Chilltrix install. I’m using it for both radiant heating in the winter and radiant cooling in the summer. Haven’t had any issues after two winters and one summer. Very efficient system. I’ll post some of my graphs tracking my energy use in the winter and summer. I’m very happy with the choice and will be buying a Second one for a shop I built that is currently being heated by a 5500 W electric water heater.

    1. lance_p | | #87

      Looking forward to some information on your system!

    2. KeithH | | #92

      Radiant chilling? How are you dealing with condensate?

  43. jchaters | | #86

    It would be great to see real world data

  44. rhl_ | | #88

    The other big news is that spacepak now has inverter driven monoblocs, and this fall(?) will have inverter driven split systems. I’m planning to install the latter.

  45. jchaters | | #89

    Do you know where the Spacepak is manufactured, as in which factory? Is it the same factroy that built Unico?

    1. rhl_ | | #90

      No idea. Why do you ask?

  46. jchaters | | #91

    Because 3000 Unico chillers are failing

  47. user-6810945 | | #96

    I live in Reno where it is very dry and I maintain the water temperature above the dewpoint. Really isn't an issue. At night I pull in cool air through my filtered outside air intakes. Just got solar with batteries installed last winter and with my electric cars and I am almost completely off the grid thanks to the Chilltrex unit.

    1. KeithH | | #98

      Cool. I also live in a dry climate and have wondered if the specialized dewpoint controller would allow a radiant chilling loop.

    2. DrewsBrew | | #99

      @user-6810945 -- I'm looking at new construction build in Stagecoach. Do you have any installer recommendations?
      Debating between in-ground horizontal Geothermal (in sand) or something like the Chiltrix.

  48. Jon_R | | #97

    It would be so nice if Fujitsu offered a low cost "to water" indoor heat exchanger for use with their XLTH systems.

  49. NotChill | | #100

    How do I get in touch with user ID Jchaters?

    Ive had a chilltrix system for almost 2 years now and NOTHING BUT PROBLEMS. P5 etc. And I've had LOTS of exchanges with Mark at hotspot, etc. I'm happy to share all this but first, Jchaters reply suggests he/she may have a solution. I'm desperate.

    Thank you

    1. charlie_sullivan | | #101

      I have no idea how to page Jchaters--maybe they'll see your comment and show up if they are getting email notification for this thread. If that fails--maybe post as a new question? I'd like to try to help, though no guarantees I'll be able to.

  50. polyakov | | #102

    I had P5 errors that I successfully resolved with Mark and John at Chiltrix. Post your question here.

    Is your error thrown when heating water or heating or cooling? And what is your water flow C13 when the error happens (in L/min)?

  51. golden2husky | | #103

    I'm updating my experience with the Chiltrix installation. Regarding the failure I experienced with the board for the chiller, I compared the replacement board with the original. On the original board there were a few "ghosted" components in the area for TVSS...for MOVs...they are all installed in the new part. Additionally, the new board came with an additional external TVSS module. So, this must have been a pattern failure.

    Since that repair, I've had no failures and no error codes. Last summer was trouble-free. The key with this unit is that it has to be commissioned. I went over a lot of what this system does and how to configure things with Mark - he was always helpful and patient - there are just a lot of parameters to set. It is not a "plug and play" unit for sure. But Chiltrix always provided information and explained why a code set, and what to do to fix it.

    Vladimir, a belated thank you for the advice on setting the unit to wake up - that is a good idea. I also found that you can see the water temperature by pressing the temp up and down buttons on the FCUs simultaneously. Which brings me to this point - they need to get their documentation in order. A lot of this stuff that causes problems could be eliminated if the printed materials were improved.

    So, after two summers of use would I buy this unit again? Yes. Just understand that the piping flow calcs are critical and you have to spend some time setting the parameters in order to get everything to work properly. I am cooling my entire first floor for the same energy cost that I used with a single 12K BTU window unit before the install. The quiet operation and the hidden installation alone made it worth it. The energy savings makes it even better!

    1. charlie_sullivan | | #104

      Very glad to hear that it worked out in the end, and that there's a good reason to expect the failures in the future will be less likely. Interesting reinforcement for the recently posted article suggesting surge protection for heat pumps:

      Thanks for sharing your lessons learned.

  52. DrJ62 | | #105

    Hi All,
    So I have this tragic story of my dealings with Hotspot Energy/Chiltrex which I believe are sister companies according to their website. I had a patient who was an AC contractor who was going to replace my 2 existing AC-freon based heating/AC units. I'm located in Fair Lawn,NJ and gave him a $20,000 check to purchase 3 CX34 heat pumps, a VCT37C SS 37 gal multi function tank, and 2 horizontal Fan Coils. These items were delivered to my dental office and placed in a garage waiting for the install. Tragically, he suffered a stroke at 54 and passed away. I spoke with John Williams immediately afterwards to tell him of what happened and he knew the contractor well. I was attempting to return the 3 units to them, as they were still on the pallets and wrapped as well as the buffering tank. Initially he seemed more than willing to work with me asking for a letter from the widow to allow him to work with me.
    Then he ghosted me, not answering phone calls, must have caller ID, or answering any of my emails. As these are brand new units, I couldn't understand what the issue is? I have no use for these products now. So be weary of who you do business with, as they were all smiles in the beginning but now don't know who I am. They also have my 2 air handlers in their warehouse and I can't even get them to ship them to me. If any one has a need for 3 brand new CX34 chiller heat pumps, reach out to me for a great deal!!!

    1. polyakov | | #108

      email me at . My member id in front , no spaces.

  53. user-6623302 | | #106

    I think your patient/contractor my owe them money.

    1. DrJ62 | | #107

      No, I have the paid invoice. It was prepaid by wire. He gave to me before his death as a copy.

      1. paulnederland | | #109

        DrJ62 how can I get a hold of you?

      2. schoeb93 | | #110

        Are these units still for sale? In am in NJ as well.

  54. Stretch2727 | | #111

    Also looking at Chiltrix units. Any updates from the people that have installed them on how they are working long term?

    1. charlie_sullivan | | #112

      If you haven't already, check out the growing list of air-to-water options in this article and the comments (where at least two more have been added):

  55. cr0ntab | | #113

    I went ahead an DIY'd an Air to Water heat pump.

    First room went operational in January.

    As of today, I have 3 room completed with 3 that get daily use.

    I should be wrapping up the 4th room this weekend.

    I'm located in Southern California and it's been quite hot - 90F+ the last month or two.

    My units seem to be working well, time will tell around longevity!

  56. Eng3D | | #114

    Very interesting info and things to think about. Would be nice to get in touch with a couple of you in the Reno/Carson City area to talk about what you've done. I'm designing a house now and still trying to decide on the final radiant/cooling equipment. So may decisions...

  57. RayMorgan | | #115

    We are an offshore subsea research company that now has four of the Chiltrix CX34 heat pumps in service. These units are used primarily to cool operations spaces and power conversion equipment that are installed inside twenty foot shipping containers on board research vessels. The majority of our work is in tropical conditions in the West Pacific and the Indian Ocean. The outdoor units are mounted on wheeled carts, exposed to salt spray, monsoon rains, typhoon winds and constant motion. The outdoor carts are wheeled into the containers for ocean container shipping. The units are plumbed with one inch flexible hose to three fan coil units in each container. There are quick-disconnect fittings in the hoses. The oldest of these units has been operating for six years without issue. When our equipment returns to Western Canada the units are used for heating the containers.

    Some things to note:
    -If the outdoor unit is installed in an area that doesn't want dripping water, the unit should be fitted with a full size drip pan with a drain hose to an appropriate place. On a foggy heating day the outdoor unit generates significant condensate.
    -The power input must have an appropriate power surge protector installed. Phase to phase and both phases to ground.
    -Setting the cooling loop temperature at ~10 celsius maintains the desired 50% humidity at 70C inside the operations container.
    In heating mode the defrost cycle works well. Cycle is quite short, ice melts quickly then the cycle ends.
    When commisioning the first unit we had 'water flow' errors. This was happening because when the system was very lightly loaded the pump slowed to a water flow below the minimum water flow setting. This issue was quickly eleiminated by reducing the 'Minimum Flow' setting in the controller menus.
    We had one failure of a water flow sensor caused by condensate entry into the sensor electronics due to an inappropiately arranged cable drip loop. The vendor, Hotspot Energy, was most helpfull in troubleshooting the issue and immediately shipped a replacement sensor that we had in hand in two days.
    I am presently planning replacement of our very old ducted oil furnace with a CX34 heat pump, a 16MVB ducted air handler, DHW40 hot water tank and perhaps a V-18-B backup heater. Backup heater is probably not necessary in our West coast climate where I don't ever recall seeing -20C.
    Water heater will pre-heat to about 45C and then feed the existing electric water heater to bring temperature up to a final 60C. A nice thing about this is that the Chiltrix unit has the sensor inputs and control outputs required to integrate and manage all of this.
    Anyhow, from my experience I can highly recommend the CX34 and the fan coil units and my support experience with Hotspot energy has been great. Price is somewhat higher that a simple mini-split, but no refrigerant mechanic and hot water to boot...

    1. Tim_O | | #116

      That's great feedback, rough environment for sure. The water flow error you mention is interesting. I follow a Chiltrix Facebook group, that seems to be a common issue.

  58. Expert Member
    DCcontrarian | | #117

    There is a Facebook group for Chiltrix owners:

    It is a private group, but you don't have to be an owner to join. I would go there if you want first-hand reviews.

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