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Community and Q&A

Heat Pump Water Heater inadequate – looking for solutions

mclola | Posted in General Questions on


Two years ago we replaced our 50 gallon gas water heater with a Bradford White Aerotherm 50 gallon heat pump water heater.   

The new heat pump water heater is set on hybrid mode at 140 degrees and is not keeping up with our minimal hot water demands (usually only 1 shower a day with one 1.8 GPM showerhead needs to be rushed through in order for the water to stay warm enough for comfort if we have used our HE washer in the 5 hours prior to showering).  There are currently 2 people living in our house.

We live in climate zone 5 (Syracuse, NY), the water heater is in our basement which maintains temperatures of 60 degrees F or greater throughout the. year, and there is plenty of room for circulation of air around the unit.

Last year we had the lower unit electric heating element replaced, and a few months ago had the drip tube replaced (both defective).  Despite mild improvement, this isn’t enough to keep up with our needs, and in a few months we will have 2 additional people living in our home (total of 4 adults).

Bradford white recommends getting another Heat Pump water heater -50 or 80 gallon plumbed parallel with the other unit.  

I’m wondering if anyone has experience with parallel plumbed water heater setup, and if it might work (if the second Bradford White unit has working parts).  

Are there pros/cons to plumbing 2 water heaters parallel vs series?

Are there other Heat pump water heater brands that might be more reliable than the Bradford White?


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  1. paul_wiedefeld | | #1

    It is broken, that’s a very low water demand and should be handled by any heat pump water heater out there. They need to fix it, another parallel heater is totally unnecessary.

    1. mclola | | #4

      Hi Paul,
      Thanks for your response. I agree it doesn't seem to work appropriately despite the recent diagnostics showing it should be. I have asked the company for a replacement (no response yet), but then wonder if the Bradford White heat pump hot water heaters may have some intrinsic flaws, and perhaps I should go with a different brand.

      If anyone has any experience with reliable brands of heat pump hot water heaters, I would appreciate input.

      1. paul_wiedefeld | | #11

        I don’t know enough to say one brand is any better than any other. If anything, I suspect they’re about the same and you got unlucky.

        As to the lower heating element - was it confirmed defective by anyone? They’re cheap enough I wonder if they just pointed the parts cannon at it.

        1. mclola | | #13

          The original HVAC company who installed the unit confirmed the lower heating element did not turn on with increased demand (I ran my shower for the diagnostics) and did replace it last year -one year after installation. This did not make much of a difference.....

  2. matthew25 | | #2

    Paul is right. 50 gallons is plenty for your needs. Side question: why are you running your clothes washer with hot water?

    1. mclola | | #5

      Hi Matthew,

      I was referring to running the HE washer with warm water or in the eco mode. I appreciate your input!

  3. Expert Member
    DCcontrarian | | #3

    Agree with Paul. From the description it doesn't sound like the water heater is providing 50 gallons of 140-degree water. That needs to be fixed before doing anything else. As a diagnostic, flip it into pure resistive mode and see if it meets your needs. Unfortunately it's hard to get the compressor fixed.

    As a point of comparison, we have a 65-gallon HPWH, set to 120F, that provides enough (just) for five adults. I've put 1.25 GPM heads on all the showers.

    1. mclola | | #8

      Based on your experience with a 65 gallon HPWH - it sure seems like the 50 gallon one should be sufficient for 2 adults. We never had issues with running out of hot water with our previous 50 gallon gas water heater either. Do you run yours on hybrid or just heat pump mode?

      I will try the pure resistive mode and see if this makes a difference.

      If you have found your current HPWH to be reliable, would you mind sharing the brand with me?


      1. Expert Member
        DCcontrarian | | #12

        I have an AO Smith. I first installed it about two years ago, the compressor failed within six months and was replaced under warranty. Twelve months after that the circuit breaker started tripping, one of the heat elements had shorted out. I replaced both elements and it's worked ever since. So I can't say it's been trouble-free, but right now it's working.

        I run it in hybrid mode. I don't know how much it runs in resistive mode. I know it does some, because when the element was shorted out the circuit breaker tripped. But it was an intermittent problem that took a while to diagnose, which makes me think it only runs resistive intermittently.

        1. mclola | | #14

          Thanks for the information - and I am happy to hear your's is working now. I just put mine in the pure resistive (electric) mode, as you suggested, to see if this makes a difference with tomorrow's shower. If it is the compressor it is still under warranty.

  4. Expert Member
    Akos | | #6

    I know it feels silly to even ask, but I've done it.

    Is the cold and hot water plumbed to the right ports and not backwards?

    You mentioned dip tube failed, which is highly unlikely on a newish unit. Lack of dip tube would have similar symptoms.

    1. mclola | | #9

      Akos, this is a good question -- but yes, the cold/hot water is plumbed to the correct ports.

      I was surprised the lower tank heating element was not working less than one year after installation, and the dip tube less than 2 years after installation. I don't know if anyone else has experience with a Bradford White Aerotherm HPWH, and if so, what their experience has been.


  5. Deleted | | #7


  6. Deleted | | #10


  7. gusfhb | | #15

    An electric HWH of the same size as a gas one will have significantly poorer recovery time as a rule
    The usage described is almost trivial however.
    I would check the temperature of the water in the tank.
    The symptoms would suggest to me that the water temp is lower than expected.
    Oh, and do check that the shower valve is not oddly defective. Had a thermostatic valve get clogged with silt and act like no hot water

    1. mclola | | #20

      These are good thoughts, including the information on the shower valve -- I will have our plumber check this. Thank you!

  8. nynick | | #16

    I have a brand new State HPWH installed last November. It is installed in a mechanical room within my newly built detached garage with an apartment above in which the two of us live. It's set to 120 degrees and is in Hybrid mode. The building is well insulated and the pex and all the plumbing is brand new. We have had zero problems, take normal showers and use the dishwasher etc normally.

    Your situation is suspect. I wonder if your pipe runs are exposed to cold weather within your walls or basement? Syracuse has some cold weather and any open cracks or crevices near your hot water supply could affect the end temperature. You need to monitor the incoming and outgoing water temperature at the tank while running the shower to determine if it is in fact at fault or if it's actually sending 140 degree water at all. Start there and work your way forward to the shower heads.

    1. mclola | | #21

      This makes sense, I will have the HVAC company that installed our water heater do this when they come yet again to respond to our FI error.... Thank you for your thoughts on this.

  9. walta100 | | #17

    When in heat pump mode does the compressor run continuously? Like it would if the tank never gets fully up to temp.

    1. mclola | | #22

      I can't tell if the compressor is running when in heat pump only mode - Also, when I place it in heat pump only mode, for some reason it still pulls on the electric (the electric light blinks on and off after using hot water, so it doesn't stay in heat pump only mode even when this is selected)??

      1. walta100 | | #26

        When the compressor is running it will make enough noise there should be no doubt in your mind also the fan should be blowing air whenever the compressor is running.

        The symptoms you describing sounds to me like the heat pump is inoperative and the computer knows it and is running the heating elements in an effort to give you at least a little hot water.

        Does the display on the unit show the letter F and another letter-number? FXX

        FI would indicate the refringent leaked out.


        1. mclola | | #27

          Hi Walta,
          Thank you for the information. Yes, an FI code comes up frequently - especially recently. The Bradford White rep. I spoke to on 3 occasions told me I needed to have the coils cleaned. I'll be back to calling them tomorrow again.

          1. walta100 | | #36

            The way I read the diagnostic chart dirty coils would set the same fault code as a dirty filter F14. I think they would say anything to get you off the phone.

            When you talk to support ask pointily what hoops you need to jump thru to get this defective heater replaced under warranty.

            The computer in hybrid water heater detects the fault and engage the resistance elements so the home owner has hot water. What I find surprising is that this brand made the choice not to heat the full tank with the elements. If it made a full tank, you would never understand you would just pay the 4 times electric bills and grumble about how little money the HPWH saved you.


  10. Expert Member
    DCcontrarian | | #18

    When my AO Smith HPWH had to be replaced, these are the diagnostic steps I went through:
    1. Verify that in resistance mode it produced satisfactory hot water. This meant the controls were good.
    2. Their tech support asked me to use a thermometer to measure the temperature of the air entering and leaving the compressor while it was running. Since there was no drop, they very quickly said it couldn't be repaired and had to be replaced.

    The instructions say the unit has to be kept upright for at least 24 hours before operating if it is tipped over during installation. This is to allow the lubricating oil to return to the compressor. They said it's very common for installers to ignore this requirement which leads to early compressor failure.

    1. mclola | | #23

      Interesting about keeping the unit upright for at least 24 hours before operating it if tipped during installation. I know our water heater was brought into the house and on its side when carried downstairs before installation. I'll see if the HVAC company that installed the unit has run the diagnostics you did, and recommend they do so if not.

  11. Mtn_hombre | | #19

    Another data point for you, I am also in climate zone 5 and have a Rheem 50 gallon HPWH in my garage (never falls below 50F over the winter). It is set to Heat Pump only, 120F. In two plus years with two of us guilty of long showers we have never had an issue with lack of hot water, including sometimes taking a shower while the dishwasher is running. Per a previous comment, we did have an issue when we first got into the house after construction where we had hot water issues in the shower. Turned out a piece of insulation had flowed into the shower mixing valve on the hot side.
    On my unit I can access temperature sensors via the display to see what tank temperatures are, maybe yours has that for trouble shooting?
    Can you run a full bucket of hot water elsewhere and confirm the hot water temp and pull a reasonable volume to test the water heater?
    Since my garage can be somewhat dusty I added a MERV8 filter on the inlet to the water heater so the coils won't get dirty and impact efficiency, possible issue in your basement?
    Good luck!

    1. mclola | | #24

      Thanks for this information. I measured the temperature of a bucket of hot water and it was ~ 130 (water heater is set at 140). I'm not sure how to access information from the unit's temperature settings, but think this is worth finding out from another call to Bradford White.

    2. acrobaticnurse_Eli | | #30

      I appreciate your mention of adding a merv 8 filter on the inlet. I was wondering about the benefit of adding a larger in-line merv 8 filter like I did with my ERV but hadn't seen anyone mention doing so with a HPWH.

      1. Expert Member
        DCcontrarian | | #31

        The thing you have to be careful of is HPWH are very sensitive to restrictions in the intake air flow. They don't have any freeze protection on the coil so they'll shut down if the air flow is too low.

  12. greenright | | #25

    I run an 80 gallon Rheem Proterra servicing 7 adults. Temp is set to 130f. No problems and I rarely see it use its resistive elements.

    There is something very broken with your setup. Do you have a circulation pump? That would kill an hpwh.

    1. mclola | | #28

      We don't have a circulation pump. I agree there is something wrong/broken after hearing about others' more positive experiences with these types of water heaters. I appreciate your input.

  13. Deleted | | #29


  14. acrobaticnurse_Eli | | #32

    It's so frustrating how often heat pumps water heaters seem to have issues. If you have never heard your compressor/fan enough to know if it's even on I wonder if the heat pump function never worked and you've mostly been limping along with one of two resistive heating elements. With my 47 gallon 25 year old lowboy electric water heater we were running out of water quickly until I found via use of an inexpensive multimeter to test the ohms resistance on the heating elements that the lower one was bad. $20 later and we haven't run out of hot water since.

    If you had circuit level electrical monitoring via something like Emporia Vue I'd be curious how often you see the heat pump pulling 4500 watts vs the less than 500 watts that would be expected from heat pump mode. If/when I install a hpwh I may make sure to monitor the circuit to keep track of it actually being in heat pump mode.

    1. greenright | | #33

      This. Install an energy monitor on the hpwh circuit and observe. When running the compressor it should start at about 300-330 watts and slowly climb to about 380 over a long period of time. Using over 4kw sporadically is when the resistive elements kick in based on some recovery speed algo. My compressor runs about 5/8 of the time and the resistive elements kick in for couple minutes every now and then.

    2. mclola | | #34

      I think you may be right about the heat pump function never working (correctly at least). Since I asked this question a few weeks ago, water heater keeps coming up with the FI error code. As Walta pointed out earlier this might indicate a refrigerant leak. The Bradford White tech. support said it means it is running only on electric when this error code comes up. I have to look into the electrical monitoring device you mention (not yet familiar with this). Is Emporia Vue something a non-electrician homeowner can set up, or should an electrician set it up?

      1. acrobaticnurse_Eli | | #35

        I set it up myself and it is very doable if your panel isn't overly full. If you're comfortable replacing a breaker in your circuit panel this is similar, but someone that isn't comfortable working inside their electrical panel would probably be better off having someone else do it as there are parts of the panel that always have power even after shutting off the main breaker.

        There are a number of YouTube videos of people installing the emporia Vue 2, shutting off the main breaker, connecting a wire to two separate 15 amp breakers for power on both phases, and adding clamps to each circuit you want to monitor so you get live monitoring on a second to second basis with a detailed history you can review.

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