Nest thermostat says it is heating, when it isn’t.

[RipBicep]

Hello,

My Nest thermostat says it is heating, when it isn’t. My workaround is to go to Mode | Off, then Mode | Heat, then wait, the heating then comes on successfully.

It’s been doing it for the last week. I rebooted the thermostat a few times and that doesn’t help, the only thing that helps is turning Heat off and back on. This means I wake up and house is cold each day.

does anybody have any ideas?

[Scottbess]

I have the same problem.  Seemed to start about a week ago.  Still haven't found the answer.

[RipBicep]

Yes, it’s been about a week also. I haven’t changed anything.

Do you find the workaround of turning Heat off and back on kicks it back into life for a while?

[Scottbess]

I did and it worked for one cycle.

[LaxActium]

The furnace circuit board may be acting up. Try a dumb thermostat first to see if issue persists. 

[Scottbess]

Great minds....earlier tonight I dug up my old thermostat and will swap it out tomorrow to try to narrow down the problem.

[RipBicep]

I my case, this is not a wiring issue, it’s the Nest thermostat

[Scottbess]

I'm sure mine is also not a wiring issue - ran great for a year.  Originally, I thought it was the furnace, but I'm starting to think it's the Nest thermostat (that's why I'm going to test it by swapping with the 'dumb' thermostat).  My initial thought was that it's got to be a software update that messed something up, but there doesn't appear to be enough of us having that problem to point to that.  Still perplexed, but working through it.

[RipBicep]

Cool, please let me know how you get on 🙂

[Scottbess]

Finally got to swapping out the nest thermostat for my old 'dumb' one.  The problem (heat for 10 mins then stop even though the desired temp hadn't been reached) still existed.  Good news - it isn't the nest thermostat.  Had a service tech out this morning and it ended up being a faulty pressure switch.  He put in a new one and the problem is resolved (luckily, under warranty).  Put the nest back in and everything is great.  Wish I had a better direction to send you, but, in my case, it wasn't the nest.

[Fletcher]

I'm having this same issue, 2 nests, and 2 separate heating units. Need a solution! 

[RipBicep]

Hi Fletcher,

just to confirm the exact issue, I am finding that Nest says “Heating” or “Pre Heating”, but the boiler is not actually doing anything.

My workaround if to turn Heat off (Mode:Off) and back on (Mode: Heat)  then the boiler fires up.

Is this what you are experiencing and does this workaround work for you?

Thanks

Paul

[Jake]

Hey all,

Sorry for the late reply. I wanted to follow up and ensure you are good to go. Please let me know if you are still having any trouble from here, as I would be happy to take a closer look and assist you further. 

Best regards,
Jake

[Fletcher]

Yep, except I don't have a boiler and what I get is the pre-fan cycling on and off but no burners kicking in. I'll lower the temp to below where it shows as heating, wait a minute, and then turn the heat back up and it works fine. Until the next time that is. 

[Fletcher]

I just ordered a cheap thermostat to replace the Nest with to see if the issue persists, but I'm 99% sure it's the Nest doing it. 

[CoreyG]

I'm also having this problem. Heat randomly stops working, usually overnight, and the system runs non-stop for hours on end as "heating" but only really blowing. It's like the thermostat randomly forgets how to heat. I can fix it by resetting/restarting the thermostat, but it's a very inconvenient problem to have. Will work fine for days at a time, then randomly stop. Anyone found a solution?

[Fletcher]

I replaced one of my nests with a 15 dollar thermostat from Amazon and presto, the furnace works just fine now. Very frustrating! 

[Chendricks]

Will you share the link to the new thermostat that worked for you? 

[Sd1]

I have similar issue - the thermostat shows that the heat is on but the furnace is not on.  I thought the circuit breaker to the furnace may have tripped but it was not because I can control the furnace fan with nest app but the heater blower did not turn on.   The workaround for me is to reset the circuit breaker and the furnace restarts.  This is happening more often now.  I am not sure what is the solution?  

[Ccpie]

I am having this issue as well. Th rowing the circuit breaker is the only thing that (sometimes) restarts the heat actually coming out of the baseboards. 

[jvnparadise]

Fletcher, did you find a fix... I see that ScottBess had a real issue with the furnace (pressure switch)... I plan to put the dumb thermostat back in as well... Had HVAC out several months ago and he gave me a clean bill of health, but he didn't stick around long enough to see the furnace kick off and the Nest continue to show as heating. My workaround is like everyone else, turn off or down and then turn it back on and voila, heating again... Anyone else find anything?

[jvnparadise]

Also, i can never reach a set point greater than 71 or 72 which seems more like a furnace issue, but....

[Fletcher]

My solution was to first install the dumb thermostat, which fixed the problem. Then I bought and Ecobee and it's working like a champ so it's 100% the Nest that was the problem, and I got tired of messing with it. Bye bye Nest, and frustrating problems, with no support or help from Google.

[jvnparadise]

Copy... thank you for the update... I'll look into it.

[CoreyG]

After experiencing a very similar issue for a while, I found a couple of potential solutions which seem to have remedied my problem. I have a heat pump and overnight typically is when the issue was occurring (when temperatures are lower). Looked into the settings of my thermostat and it was set to never use alt heat (the backup/emergency coils in my blower). These were functioning when testing the unit just fine, but during normal operation they were not kicking in as a result of the setting. I've adjusted my alt heat setting to kick in at 35 degrees and haven't had a problem since.
I also read about issues with the o/b wire setting being set to 'seasonally' which doesn't work as intended. I've changed this setting but I'm not sure how necessary it was to resolve the issue, as I haven't had a problem since and don't want to risk having it stop working on me again.

[Fletcher]

I have 2 new Nests that I had to uninstall, and replace with other thermostats. The Ecobee, and a "dumb" thermostat both work without any issues at all. So over $400 in Nest thermostata that are worthless to me. 🤬

[D-Anon]

I might follow suit and try that Ecobee. My Nest has been running my system nonstop because it is cycling between compressor and aux heat to heat up the space and then using just the compressor as the temp gets close which blows colder than room temp air resulting in bring the room temperature back down.

[Fletcher]

Worked for me, just sucks having to buy another $200+ thermostat to address the issues with Nest vs Google being attentive to the issue and providing a solution!

[Sd1]

Thank you for your responses.  I am considering switching to alternate thermostat.  Seems like Nest has some fundamental bugs that can not be fixed in my case with setting or by other means.  I also learned from some post that Nest does not support variable speed furnaces which is what I have. 

[iMan]

Hi everyone, I have the exact same problem starting in November, and after chatting with google support they insist its the common wire problem, have you tried that ? I feel like this is a SW issue but who knows ! 

[D-Anon]

Have you measured the discharge temp of your ducts before and after heating is called for? It's really hard to trouble shoot and figure it out without all the data. Mine was heating but not enough to raise the temp without aux heat when it was really cold. So the thermostat was up against the limits of the system and not "smart" enough to know it. Honestly this could be done\fixxed with the right programing but I'm not being paid by nest to develope it🤣.

[iMan]

Mine doesn’t turn on when this happens, I played with the Rc wire and seems like it’s kinda working, but still happens once in a while, this is a code problem

[Fletcher]

Common wire didn't make a difference on mine. Wish it were that simple. 

[iMan]

I figured, it can’t suddenly be the problem, do you have to use common for Ecobee thermostat?

[Fletcher]

Yes, I did use the common, but the wire was there already so not a problem. I also used it with the Nest, but it did not change the behavior at all.

[Dpcameron13]

Same issue here. Turning off and back on fixes it. Still no solid resolutions? I’ve tried resetting my Nest completely. 

[iMan]

Not really, I did tighten some of my wiring, but not sure if it helps, it’s very inconsistent for me, I’m amazed the software can’t handle this situation, if it’s not warming up try off and on again Nest!!

[SenorHass]

I am suddenly having this exact same issue, it will say heating, but won't actually be running. Then if I turn the thermostat to off and back on to heat, it will work. However this morning while it was saying "pre heating" it would act like it was heating for a minute or 2 and then stop without the fan every coming on. So then I tested turning on the fan with the thermostat, that worked. So I deleted my entire schedule in the app and now it appears to be working. Everything I can see looks like it's a sudden issue with the thermostat, which would indicate a software bug

[Wirenut]

Nest thermostat will not start furnace, when time says to come out of set back mode. This has occurred three times now. The fix I used was turn stat to OFF then wait two minutes then back to ON.

[Trynnye]

Tried and heater still not coming on home still cold