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Heating stops before reaching desired temperature

ocowley1
Community Member

Hello, 

I have recently moved in to a new house with a nest thermostat. I set my own schedule and it was working. But recently, it has started to turn off the radiators before it gets to the set temperature, e.g. it will often stop at 17C when I want it at 20C. 

I have reset to factory settings and checked the programming. It says 20C all day and never gets there. I have latest software updates on thermostat. I tried charging the Nest last night as well. 

Thermostat sits in the middle of the house away from any sun light. I have managed to 'trick' it into working a couple of times, I can get a short burst if I test the heating (where it says its fine) and all the radiators turn on. Also, if I turn the heatlink lights on to override and then wait and turn it off it kicks start the heating. 
Also, once I managed to turn the heating off and have it come on with the schedule in 5 mins and it came on. 

I turned off auto-schedule, time-to-temp, true radiant, and sunblock on the app thinking that would resolve things but it hasn't. I have turned the eco temp and safety temps both off.

Any assistance would be great. Thanks

6 REPLIES 6

jenniffert
Community Specialist
Community Specialist

Hi ocowley1,

 

Thanks for reaching out to the community. I'm sorry to hear that your Nest thermostat is unable to reach the desired temperature of 20°C and stops at 17°C. Even after performing a factory reset and deactivating some smart features, it still isn't reaching 20°C. Help’s here!

I appreciate all the workarounds already done. This can definitely help us move forward to the next steps. Based on the information provided, it seems like you're located in the UK. Can you confirm if this is correct?

Additionally, to continue investigating the case, I’d like to ask the following:

  • What is the model of your Nest thermostat?
  • When was your Nest thermostat installed?
  • Do you have more than one thermostat? If so, do other thermostats have heating points that can explain the activation
  • Is a vent close to where the Nest thermostat is installed?
  • What type of system or combi boiler do you have?
  • Have you made any changes to the heating system?
  • Have you recently had service or maintenance on your electrical or heating system?

Please keep me posted.

 

Best regards,

Jenniffer

Hi Jenniffer, thanks for getting back to me. Yes, I am based in the UK. 

Answer to your questions:
- Model is Nest 3rd gen learning thermostat
- We did not install the thermostat, so don't know when it was installed. We moved in in December and it was already installed and working. 
- We just have one thermostat
- No vent near the thermostat, it is in the middle of the hallway. 
- We have an air source heat pump which heats hot water in a tank for central heating through radiators. 
- Haven't made any changes to the heating system. 
- No recent service, but when we bought there was a check on it and it worked. 


It is strange, because the system all appears to be working (e.g. when I run a test) and the heating does come on, it just comes on for a bit and then stops well below the desired temp. 


Thanks

 

jenniffert
Community Specialist
Community Specialist

Hi ocowley1,

 

Thanks for following up!

I really appreciate all the information provided and confirming that you're located in the UK. 

To continue investigating, I'd like to ask the following:

  • What is the color of the Heat Link status light? For reference, you can check out this article: Heat Link lights and what they mean.
  • Are you using the Nest thermostat in a manual mode?

In the meantime, I'd suggest the following steps:

  • Check that the wires are securely connected. Important: Before touching any wires, turn off the power to your HVAC system at the breaker box.
  • Check the air filter. The HVAC system needs good airflow to work properly.
  • Perform a restart on the Heat Link and the Nest Learning Thermostat by pressing and holding the Heat Link button and the thermostat's display for 10 seconds, then releasing it. For reference, you can check out this article: How to restart Heat Link or reset it to factory defaults.
  • If possible, maintenance should be performed to determine whether the motorized valve (zone valve) or appliance that the Nest thermostat is controlling is malfunctioning.

Please keep me posted.

 

Best regards,

Jenniffer

Hi Jennifer, 

Answer to your questions: 

The Heatlink shows 'Steady green' with the heating and hot water lights off. I don't think I am using the thermostat in manual mode, I can control it through the app. 

I have worked through those last steps and get the same. However, I have noticed that the reason the heating is not working is because the hot water is on. I switch the hot water off and the heating comes on. I have set a schedule which alternates what is on every half an hour, but I expect this should not be the case. 

Weirdly:

Hot water OFF, Heating ON: only heating on

Hot water ON, Heating OFF: only hot water

Hot water ON, Heating ON: only hot water

Have you come across this issue before? I can't see similar in other community posts

 

Thanks

jenniffert
Community Specialist
Community Specialist

Hi ocowley1,

 

Thanks for your reply!

I appreciate you detailing the behavior of your heating system. Since you've mentioned that the heating isn't working while the hot water is on, it seems like the inconvenience might be related to the initial settings.

The team would like to learn more about this behavior. When you get a chance, please fill out this form and let us know when you’re finished. We’ll have someone reach out to you via email from there.

Please keep me posted.

 

Best regards,

Jenniffer

jenniffert
Community Specialist
Community Specialist

Hi ocowley1,

 

We haven't seen your submission form come through yet. Were you able to access it okay? Let us know if you're running into any trouble or still need our help!

Keep me posted.

 

Best regards,

Jenniffer