Thermostat Wiring and Operation (with Heat Pump)

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My system is working at this point after I deleted and reset the thermostat and changed the wiring (see the Dropbox link below). However, as others have said I’m concerned that it is not working as efficiently as it was with the old thermostat. Also, I have lost the basic functionality of manual control of the auxilary/emergency heat and the indicator that manual/emergency heat is activated.

Below is the exchange in progress with support including my system details, a link to wiring details and the screenshots they asked for. Note that Wyze support has indicated there is a “Differential Temperature setting” and the ability to activate the “emergency auxiliary”, neither of which I can find.

Re: [Wyze Ticket XXXXXX] Re: Thermostat not working correctly

Tue 12/29/2020 12:41 AM
The Emergency Heat and the Auxiliary Heat are the same on my unit (electric heat strips within the unit). The old thermostat has a setting for “Em Heat” that can be used to manually activate the heat strips in case the compressor unit fails.

My system is composed of the following equipment installed in 2015 (the wiring diagram in the Dropbox folder link below is from the Trane system documentation):
Trane 4TWR4 Heat Pump
Trane TEM4 Air Handler
Honeywell FocusPro 5000 Series Thermostat (replaced with Wyze)
Documentation for these is easily found online.

Phone: Google Pixel 3 XL running Android 11

Here is a link to a Dropbox folder that has screenshots and pictures:

Thank You,

From: Support support@wyze.com
Sent: Monday, December 28, 2020 8:58 PM
To: <'s email>
Subject: [Wyze Ticket XXXXXX] Re: Thermostat not working correctly

##- Please type your reply above this line -##

Your ticket (XXXXXX) has been updated. To add additional comments, please reply to this email.

Sharlyne (Wyze)

Dec 28, 2020, 5:58 PM PST
Hey there, !

Kindly send us a screenshot of your Wyze App on the thermometer. Also, can you please clarify which heat were you referring to? Is it the Emergency Heat or the Auxiliary Heat?

Thank you and we will wait for your reply.

Sharlyne | Wyze Wizard

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Dec 28, 2020, 12:08 PM PST
Thanks for your reply. Can you explain this please?
1.) Where/How do I find the “Differential Temperature” settings? How do I access this setting?
2.) Where/How do I find the setting in the Wyze app and on the thermostat to manually activate the emergency auxiliary?
3.) Again, is there any indicator in the app or on the thermostat to indicate when the auxiliary or emergency heating has been activated?

Sharlyne (Wyze)

Dec 28, 2020, 11:32 AM PST
Hi , thank you for your reply.

Wyze Thermostat has a Differential Temperature setting available which allows you to customize the threshold for when the heating or AC will turn on. This allows you to set the threshold for when your heating or AC will turn on, with a range between 0.5-2.0 degrees in half-degree increments. This allows you to fine-tune your system to work how you want.

About your question, once the4 compressor fails, the emergency auxiliary can be activated from the settings of the Wyze app and on the thermostat.

We hope that helps! If you have any additional questions, please reply back to this email so that we can assist your further.

Thank you for being part of Wyze. Stay safe and healthy!

Sharlyne | Wyze Wizard

Visit our Help Center: click here
Website | Facebook | Twitter | Instagram | YouTube

Dec 28, 2020, 7:19 AM PST
Thanks for the response. I have it working now but I’m not entirely sure it’s working correctly. I’d like to know how the thermostat operates when using a heat pump. Could you please answer the questions below?

What conditions cause the 2nd Stage or Auxiliary heat source to be activated?
Is there any indicator to let you know that Auxiliary/Emergency heat has been activated? Is there any way to know this?
What happens if the heat pump compressor fails, is there any way to activate Auxiliary/Emergency Heat manually as there is on most heat pump thermostats? I don’t see any way to do this.

Thanks,

Wyze Thermostat With Heat Pump
23

I had an issue with how to handle the white wire wired to Aux/E which is my heater coils. Wyze told me to wire to * and then when I set up the app it asks what is wired to * and I tell it emergency heat.

I had the same question, how does it know when to kick on the emergency heat? Also it will get cold enough at my latitude where the heat pump is ineffective. Does it also kick on emergency heat based on outside temp too. Most units do I thought and that would be the time I will really need it to be smart enough to automatically do it.

I do know there is a manual override in the thermostat to run on emergency heat but when it’s on everything else seems to be locked out. It’s single purposed to emergency heat.

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Thanks Hayj. I was reading the other thread with this issue also and you gave me an idea. I tried playing with the app and told it I had a connection to both Aux and E. This results in Aux,Aux1 mapped to W1 and E mapped to *. I’m wondering if we tried this and jumper * and W1 together if this would work and give us the same functionality as the old Honeywell t’stat (Wyze says it doesn’t use jumpers)?

You go first! Maybe the Wyze will sense the jumper and report a fault? Or will it function as it should with an Emergency Heat mode like on the old t’stat?

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This is my problem also. I noticed the heat coming out of the vents was really hot, and I know the heat pump itself doesn’t get it that hot. My aux heat is kicking on too much and my electricity bill is projected to be at least $100 MORE than other January months with about the same temperatures outside. This is not good!

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My concern as well. I am considering disconnecting the wire for the heat strips until this gets resolved.

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I swapped back to my old thermostat because of this. The one thing about disconnecting the heat strips, is I believe it also uses them during defrost. Though if you don’t mind it blowing cool air for a few minutes, probably not a huge deal.

I have a conversation going with one of their thermostat people who said it should be based on the temp differential, not a timer. I’m going to swap back tonight to try to get a log file for them.

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Let me know if I can help with anything. I am keeping mine on for the time being but I can’t go the whole month like this. With my system the heat strips do come on for a bit during the defrost/reverse.

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I had the same problem , of the axillary coming on too often. What I did to solve it temporarily is to disconnected the white wire to heat w1 or aux whatever you want to call it. I’ve then connected to short wire between w1 on the thermostat to a toggle switch then wired the white wire I had disconnected to the to the other side of the switch. That way I can turn on the auxiliary heat or off whenever I want. By doing it this way it does not affect the defrost because that is commanded from the heat pump itself not from the thermostat.

If you want to get fancy. You could extend the white wire outside and then back to the thermostat W1 in the house, Then on the outside breaker wire with hydraulic thermostat that’s adjustable from 0 to say 40 degrees. That way you can control when the auxiliary heat comes on based on the temperature. An example of this is “OT18-60A - Goodman OEM Replacement Heat Pump Outdoor Thermostat”

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Maybe I’ll disconnect the white wire for now. I don’t know if that is a good idea. Outside temps aren’t bad and would not call for heat strips. Again this morning my thermostat needed to be satisfied 1 degree between sleep and home mode, and the heat pump along with the strips were on. There’s no way the strips were needed and it is costing me a lot of money!

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@mouse74 So if I switch my unit so the heat strips are connected to * and tell the unit its emergency heat the unit will still use them for defrost since it’s controlled by the heat pump itself? I’m in KY so temps don’t get too cold here. 20’s sometimes, 10’s very rarely. I think I could get away with the heat pump and emergency. Plus I have split units and this unit heats the upstairs bedrooms and bathrooms only, the main floor and basement are heated by a gas furnace. Emergency heat is starting to make more sense for my configuration,

Just wish the slider would basically set it this way if we set it to max savings and have this control in software.

1 Like
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Yes I think that will work for you hayj. I may give it a try too. Then I can get rid of my toggle switch and make it look nicer. My heat pump balance point is about 14 degrees.

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On my old honeywell I had white connected to AUX and a blue on E, which I believe is emergency heat. I think now I have blue on * and configured the thermostat to say * is emergency heat.

I will double check but if white is on a W terminal on Wyze, I think I can disconnect that for now to prevent the heat strips from coming on when the stat demands it. Does that sound right?

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Scott I agree with your summation that will work for you. Where I’m at is I don’t have emergency heat at all I have is auxiliary on w1. I didn’t want emergency heat coming on every 30 minutes so I broke the w1 wire are coming out of the thermostat and now I have no auxiliary. I can always put it back if we get a cold spell. For now in Tennessee I don’t foresee needing it anytime soon and hopefully they will get the software updated in the thermostat. Removing the white wire or W1 will not stop the auxiliary from coming on on during a defrost cycle.

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I disconnected the white wire from W1 and that stops the heat strips from coming on.

Is there an official bug request or report, some support ticket already open that I can also tag onto? I have used at least 50% more electricity since I switched and this is obviously unacceptable for numerous reasons.

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Thermostat - 2 issues now
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Sorry if I missed anyone stating this, but did you move your Behavior slider to “Savings”. This should help with the heat strips kicking on when there is a high temp differential.

Here in the Carolinas, our Mechanical Code requires us to install outdoor thermostats to lock out heat strips unless it’s 40 degrees or below. This overrides any thermostat trying to energize the heat strips. While it’s not ideal, it is an option. Heat Pumps can effectively heat a home down to -20 degrees outside here in the South East. The heat strips are for supplemental heat, if or when the heat pump can’t keep up. Or if the homeowner wants to heat their home quickly.

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Here is a post with my old wiring and how the thermostat is behaving now.

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I did slide the setting as far to Savings as it would go, but it would still kick on the heat strips and it seems to happen more toward the end of the heat cycle. It seems like the thermostat is trying to figure out how long it would take to reach the set point, and says “woah I need to kick in extra heat or it will take a long time!” and then kicks in the strips. In my case, I am only going 1 degree or so, and it always says “heating to 70 in <1 minute” but it always takes a lot longer. The stat seems to think kicking in the strips will heat faster and thus run less and save energy/money, but it is not. Kicking on the heat strips costs a fortune and is not energy efficient. Without W connected my heat pump runs longer and takes longer to reach set point, but is MUCH more efficient. I’m in Missouri and outside temps are 30s-40s so the heat pump has no problems getting the house to 70 degrees without the need for the heat strips. I hope this can be fixed because this situation certainly isn’t going to help with any energy star ratings.

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Not sure about an “official” bug report. I submitted a ticket, and got the response back that the ability to adjust the aux heat setpoint/offset is temporarily disabled in the app due to ongoing bug fixes. In addition, I have an ongoing conversation with one of their people on here who requested a log and said that aux should only kick on with a >2 deg differential (we know that’s not the case). I just re-installed mine (I removed it since I didn’t want a $$$$$$ electric bill), so will hopefully have a log showing the issue at some point today.

You can always submit a support ticket, since they haven’t responded to any of the threads on here, they need to realize this is a huge issue for people. As in, I will be requesting a return if it’s not fixed soon. The idea behind a smart thermostat is to save energy, not use more! Being an aerospace controls engineer, this is NOT a hard problem to solve.

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Thanks. I will submit a ticket and maybe enough tickets will get someone’s attention about it. Maybe a few social media posts are in order to get someone to respond.

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@scott2020 did you start another support ticket? I’m having the same issues. I have not changed the original wiring config.

Thanks for any help!