Thermostat overheating while on (running)

Sigh, this is the second one that is doing it. Turning it off via the app lets it cool down but it repeats itself. Sometimes removing it from the wall and adding it back fixes it, but having my AC when its less than 68 degrees outside overnight and when 4 room sensors are at or below 70 degrees but the main unit is at 78+… frustrating.

Giving up on this; thinking I really need to keep Wyze in their lane of Cameras and Home security at this point; even though they’re failing on both of those objectives a few times over the past year.

PS I’m on the latest firmware too.

I have been using my Wyze thermostat and it has been the most stable Wyze IoT I own.

I’m having a bit of confusion trying to visualize the problem you are having. Please correct any misconceptions… but here is what I understand:

You have the thermostat Heat To setpoint at (? Somewhere around 70 ?). You have 4 Remote Sensors (? Set as included in Comfort Control during the home\sleep state this issue is happening ?) And the thermostat keeps heating the space to above the setpoint? How far above the setpoint?

Or, is the thermostat itself hot to the touch and thereby increasing the temp sensor reading for the room where the thermostat is installed, thereby not heating the space when it really should be? Do you have the capability of measuring the temp of the thermostat surface? Maybe a laser thermometer? What is the reading differential if you place a room sensor on the thermostat? Does it also increase temp from the radiant heat of the thermostat?

Or, is it that the Thermostat is reading a temperature measurement of 78° when the space temp\surface temp of the thermostat is actually 70° or below and not heating the space? If this is the case and your remote sensors are all registering at 70° or below but the thermostat is showing 78° (when it’s really not), there may be an offset issue in the Temp measurement which can be corrected in the settings.

You mentioned AC. Is your thermostat set to Heat mode, Cool mode, or Auto Mode?

What is your Cool to set point if in Auto mode?

Previously saved Schedules will override all Preference settings and will NOT update with new settings if you change your Preference setpoints for the three states. Make sure you don’t have any schedules saved that may be changing the setpoint without you knowing it.

In the Advanced settings, what are your Differential Temp and Temp Correction set to?

Hoping we can get it back in line once we get some more details. Thx!


It’s only set on cool, I’m in SoCal.

There are 4 remote sensors on the upper thermostat (damper controlled, central air), a lower wyze thermostat with 2 remote sensors, the lower rarely ever kicks on given that if the upper space will warm first, cool will come on and the downstairs remains colder than the same set point of 74 degrees. Motion Enabled cooling is not enabled. I do not have Temp correction set on (currently and while its on it makes day time comfort more unbearable), diff is .5 (I have solar and battery storage).

I have scheduled set for the upper thermostat to lower the normal setpoint of 74 degrees to 73 at 9PM, then to 72 at 10:30PM. So as you can imagine this is going to run for a little bit, usually 30 minutes to an hour.

While it was running last night it kept cooling because the average was being skewed by the upper thermostat, while each remote sensor read between 68-70 degrees (one of the remote sensors is in the same space of the thermostat too), the thermostat itself was still above 78. I restarted it a few times via the app, but then just ended up setting it to off. Again while its set to off (so no fan or cooling mode actually running) the thermostat temperature dropped quickly and around the same temperature of the rest of the remote sensors.

This is the second unit (in the upper) that has exhibited this behavior. Bought an Ecobee for the upper unit that I’ll be picking up today, I’ll keep the Wyze down below for now. I replaced my Smart Honeywell system only because it kept having Wifi Connectivity/Cloud connectivity issues and thought I’d give Wyze another try when they introduced the room/remote sensors

Oh one more thing, when I’ve used my laser/temp gun in the past the Thermostat itself is considerably hotter ( the top section) than the surrounding area.

Great info. So it looks like the unit itself is overheating when it is running in cool mode, thereby heating up the temp sensor in the thermostat, which suggests to me there is some sort of continual power running back thru the thermostat that is overheating a component within it. It may be something with the wiring\AC unit.

Tagging in @speadie, the community’s resident HVAC wizard, to see if there is a specific wiring\power issue that might cause the thermostat head to overheat when the AC unit is in active operation.

Yeah the odd part is it only seems to occur later in either the early evenings or late at night. Like middle of the day (hot summers this year right) it doesn’t do it even if the AC has been running for hours.

I’ll recheck the wiring too to see if there’s current.

FYI my place was built in 2015, there’s only G,W,C,Y,R wiring.

Hmm. I don’t know of anything that would cause the thermostat itself to heat up offhand. Perhaps the power to the thermostat is outside the standard voltage, and the thermostat has a linear regulator that is overheating?

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If you swap the thermostats, does the problem migrate, stay upstairs, or go away?

Second thought… There isn’t a hot water pipe behind the thermostat in the wall is there? Have you measured the wall temp when it does this?

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No there’s nothing behind this section and yeah wall temps are close to ambient temps.

Nominal voltage is 24v? I’ll measure it now

[quote=“SlabSlayer, post:8, topic:244728, full:true”]
If you swap the thermostats, does the problem migrate, stay upstairs, or go away?

Second thought… There isn’t a hot water pipe behind the thermostat in the wall is there? Have you measured the wall temp when it does this?
[/quote]Because it is hard to reproduce at times, I can’t say.

The first time I contacted support to swap it out that’s what I did I swap the bottom for the top to check it wasn’t occurring.

Upper is measuring (R to C) 27volts, Lower is measuring 26.7 volts

Which I believe is in operating range (20-30v); not sure what the Wyze specifically needs.

You moved the upstairs thermostat downstairs and the downstairs thermostat upstairs. Did the problem then reproduce upstairs on the second thermostat or did the problem then move downstairs along with that thermostat?

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Is that the voltage when the system is idle w\ the thermostat off the mount or when it is actively cooling? You said that it heats up only when it is cooling.

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I’m really hoping this is fixed. Ok so tested R to Y, 27.1 volts (all tests is with Thermostat off and wires not jumpered).

Swapped Downstairs to Upstairs, turn on cooling, Thermostat heats up within 5 minutes, 4+ degrees. Ok now the problem is following, something wrong upstairs consistently.

Went to Best Buy to pick up the Ecobee and some unrelated items. On the drive home, thought about it more, did I replace the jumper panel when I RMA’d the first unit (this was months ago)?

Got home, I still had the box, swamped the jumper panel. Testing cooling mode, more than 8 minutes in Upper Thermostat isn’t heating up so far and actually dropped a degree which is a good change.

I do apologize with the ranty first post, Bad night’s sleep with with what was going on. I hope this was the problem.

Last Edit Yes I did re-seat the wires (all) in the jumper/terminal box as part of troubleshooting in the original unit and today. I have no clue why the jumper box would cause any of this, its a dumb piece of metal and plastic, but if it’s fixed, that’s all I care about.

Yes. That indicates the location wiring and not the thermostat.

Do you mean the wall mounting plate that the thermostat plugs into?

[quote=“SlabSlayer, post:15, topic:244728, full:true”]
Do you mean the wall mounting plate that the thermostat plugs into?
[/quote]Yes, the one with the little leveler on it. I guess I just took the (brand new) RMA’d unit out of the box and plopped it in the first time. LIke I said I definitely re-seated all the wires in it as part of troubleshooting to eliminate it.

When I got back from Best Buy I took that piece out of the box, swapped it in and did the test. I’ll report back tomorrow if it’s still fixed. Fingers crossed that did it and I’ll return the $300 dollarish Ecobee with Room Sensors :slight_smile:

Thx. Just wanted to get the right part into my memory bank in case this issue comes up again down the road.

I guess it is possible that there is somehow a manufacturing defect in that wall mounting plate that was either causing power to bleed from the R into another pin and backfeed into the thermostat or arcing on one of the pins causing it to heat up.

Do a full close up inspection of the plate to see if there is anything visible that would indicate either of these issues.

If you still have the last thermostat from before the RMA, you might now have a 3rd unit for backup.

Hope it works! Good Luck! :crossed_fingers:

So far so good. I’ll report back in a week if nothing happens. Lol going to go return that Ecobee

Now the only thing I’m hoping for is Wyze gives us back Fan Cycling back in scheduling like it was there originally ! :slight_smile:

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I remembered I forgot to reply back with an update.

I can say I haven’t had an issue since.