Remote sensing options for Mitsubishi Mini-Splits
I’m looking to for a remote temperature sensing option for a ductless mini-split to better align the run time/modulation with temperatures in an adjacent room. I’ve heard a lot of people mention the MHK2, which looks great, but is quite expensive.
In this thread: https://www.greenbuildingadvisor.com/question/multi-zone-mitsubishi-hyper-heat-ashp-overshooting-setpoint-in-heating-mode
biggytre mentions another option: PAC-USWHS003-TH-1 remote temp and humidity sensor.
(biggytre, feel free to chime in, I just wanted to split off that thread)
I’m a bit confused how this works. It looks like it needs the PAC-USWHS002-WF-1 wireless interface. Does the MHK2 need that as well anyways?
And does the remote temp sensor actually control the unit? The literature is really quire confusing and there are lots of control products out there!
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The MHK2 uses redlink, and I think has a different interface module in the head.
The remote sensor and PAC-USWHS002-WF-1 use bluetooth to communicate, and the intention of PAC-USWHS002-WF-1 is that you'll then use the kumo cloud phone app to control your heads.
The little cube made a huge difference with keeping the temp more consistent.
So am I understanding correctly that those two PAC units can together do what the MHK2 does in terms of acting as a remote thermostat? I don't see why I'd need the MHK2.
Could we still use the stock handheld remote in addition or in leui of the kumo cloud app to set the temp, fan speed, etc.?
From the FAQs:
Can I use both the remote controller and the app?
Yes. Whichever control was adjusted most recently takes effect.
http://s3.amazonaws.com/enter.mehvac.com/DAMRoot/Original/10006/kumocloud_2.16_Owner-Manual.pdf
And yes, the wireless interface and bluetooth temp sensor do the same as the MHK2.
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"How exactly do you tell your system to use the Kumo puck as the temperature sensor for the system rather than using the sensor built into the air handler?"
This is kind of what I'm wondering too. Maybe it's obvious once you dive into the install, but as far as I can tell, the literature doesn't even mention how the data the remoter sensor provides is utilized by the unit.
*edit
Reading more on it, it's not explicitly stated, but it does seem apparent that it will control the unit.
I found this:
"Up to one Wireless Sensor may be configured for each Wireless Interface."
So it sounds like, no, multiple sensors cannot control more than one interface/unit (?).
I am also concerned by this, from the technical manual https://mylinkdrive.com/viewPdf?srcUrl=http://s3.amazonaws.com/enter.mehvac.com/DAMRoot/Original/10006\kumocloud_2.16_Technician-Manual.pdf
"(Recommended placement is within 10 ft of the Wireless Interface or indoor unit,
unobstructed.)"
That's not exactly what I had in mind. 10 feet doesn't buy you much.
For those using these, are you staying within 10 ft.? I don't understand that recommendation because Bluetooth should be able to go much farther.
10 feet is garbage. Excludes most attic and crawl space installations. Actually, I'd say excludes most installations, period. Hah.
I have 7 of them and a few are significantly further than 10 feet. I didn't even know that was a recommendation. Some of mine are like 30+ feet away from the indoor unit.
If you are price sensitive about remote sensing options I suggest you just extend the indoor unit sensing element using some thermostat wire. Most indoor units have the supply sensor readily accessible inside the intake. Just splice the 2-wire extension and solder it (dont use twist caps). Insulate each solder accordingly so they dont short.
Interesting idea
If you look at the official Mitsubishi remote sensors that is pretty much what it is:
http://www.mylinkdrive.com/USA/Controls/Auxiliary_Components/Temp_Sensors_and_i_see_Sensor/M21EAA307?product
It even connects to the same connector. If you don't want to modify the internal sensor and wiring you can pick up the internal sensor as replacement part and extend that.
So Akos, is that part you linked the replacement for the stock internal sensor, or a different purpose built remote sensor? If the latter, why not get that vs a replacement for the stock internal?
It is the official wired remote temp sensor. It plugs into the indoor temp sensor connector so it essence it does replace it.
The issue is the remote senor price is silly, close to the cost of a thermostat. The replacement indoor sensor plus a couple of feet of wire required to DIY-it is about 1/4 the price.
I have done a few like that and they work well- no different than having a remote sensor or wall thermostat, but costs literally the cost of the thermostat wire and maybe a small plastic enclosure for the rehomed sensor