NEST doesn't start the heating although it looks as if it is active

[Whippetg]

We have had a NEST thermostat since 2020 to control our heating and hot water.

All was fine until Sep-23 when it periodically had issues with the heating only. Sometimes it wouldn't start the heating, although on the thermostat and app it showed the heating was on.  Magically the issue resolved itself after about 2 weeks.

Now it has started again - 3 incidences since Sunday 4 Feb-24. 

NEST is currently activating the hot water as per schedule and sometimes it activates the heating, but not always. Our boiler engineer checked in Sep-23 that all other parts of the system are ok, eg valves. 

The solution atm is to turn off the heating and then turn it on again... although if I wanted to run my heating manually why get NEST!

Has anyone else had this problem?

[zoeuvre]

Hi Whippetg, 

Yikes! I'm sorry to hear that your heating does not activate even though the thermostat shows otherwise. Let me take a look at this for you. A few questions: 

• Are you located in North America or Europe? 
• What type of Nest Thermostat do you have? 
• Is the Nest Thermostat newly installed?
• Did you use the Compatibility Checker tool to confirm the thermostat's compatibility. 
• What type of furnace do you have? (gas, electric, etc.)
• When did heating last work? 
• Did heating ever work with the Nest thermostat? 
• Did the heating work with the previous thermostat? 
• Did you turn off the power to the HVAC system? 
• Did you recently turn off any breakers?
• Have you recently experienced a brownout or blackout? 
• Is there a light switch near the heater that controls an outlet? 
• Did you select the correct fuel type? 
• Do the LED lights blink on the HVAC control board? If yes, locate the light. 
• When was the last time you changed the furnace's air filter? 
• Have you experienced extremely cold weather lately?
• Is this the first notable temperature drop of the year in the area?

I'll look forward to your response. 

Best,

Zoe

[Whippetg]

Thank you for your reply Zoe.

We are in Europe, we have had the same NEST Learning Thermostat since 2020. We have gas.

It worked fine until Sep-23 as I say above, then recovered after 2 weeks, then just went wrong again.

We have not made any changes whatsoever and the weather is not very cold (it was colder in Jan-24).