Nest thermostats not turning heat on

[Jamesc1]

Currently unable to turn my heating on using the thermostat. I can manually turn it on using the heat link and can turn my hot water on by the thermostat but not heating. The app on my phone is the same. I had someone check the valves but he said they were all opening fine. Ideally would like to get it fixed with temps dropping so I can heat the house using my phone again. Thanks

[AlexD]

Thanks for reaching out to us here @Jamesc1 . I am sorry to hear you have difficulties controlling the heating. I'll do my best to try and assist you with this. 

First to check, how long has the thermostat been installed for and working as expected before this behaviour occurred?

You mentioned you had the system checked, which is great, do you happen to know if you have a S or Y plan type of valve system? 

Let's also do some tests to see how the relays in the Heat Link behave. Go next to the Heat Link and open the Nest app on a mobile device:

1. Select your thermostat to access the heating controls and make sure the screen is black, heating is off.
2. Turn up the temperature until the display goes orange, heating on, and listen for a clicking noise.
3. Turn the temperature back down until the display is black again, heating off, and listen for a clicking noise again.

Let me know what the results are.

[Jamesc1]

Hi alex

i think it has roughly been installed about 4 years now. I had a new heat link sent out but since then it hasn’t worked. I have had someone come to check the wiring and they said it was fine. 
I’m  not too sure on the type of valve but it’s separate for my hot water and my heating and I have a system boiler. 
when I turn the heating on by my phone I can hear a click sound and it makes the same click sound when I turn it off again

thanks

[AlexD]

Thanks for the information. Based on that it would seem the Heat Link is behaving as expected. When you turn the heating on or off we expect to hear a click as the relay inside of the Heat Link moves.

You mentioned you had the Heat Link swapped and this has been occurring since then. How long ago was it swapped? 

Also, if you are comfortable with it, would you be able to take a picture of the wiring, just to have a look in case something jumps out? If you are able to do so, make sure to turn the power off before taking off the cover for the Heat Link. 

Another thing I would like to try is to turn on your hot water, just boost it from the Nest app for 1 hour and after turn on the heating and see if after a few minutes you notice activity from the boiler and the radiators getting warm. 

[Jamesc1]

I had it replaced in august but I wasn’t trying to use the heating until around October so don’t know if it worked at all since the new one was put in. Although a day before I tried to turn it on there was a power cut so don’t know if that could have done anything? 
I have just tried turning the water on in the app then the heating and that seems to have worked for turning the radiators on. The hot water always worked on the app but that’s the first time the heating has worked. 

[Jamesc1]

 

[AlexD]

Thank you for the picture. The wiring seems to be about what we'd expect for a S plan system since there is no wire in terminal 4. Do the test I mentioned previously and let me know if you hear the clicking noise when you turn the heating on and off. You can do the same for the hot water side by turning the boost on and off, just make sure it's not scheduled to be on. 

If you know where your valves are you can repeat the test but sit next to the valves and see if they activate when you turn the heating on/off and the hot water. They might make a noise or have a status LED or an indicator to show when they receive a command. 

[Jamesc1]

When I turn the hot water on I hear the click and again when I turn the heating on just after I hear a click. When I turn the hot water on I can hear the boiler firing up, I then turned the hot water off but the heating was still on and you could hear the boiler turning off again even with the heat left on. 
unfortunately I can’t get to them at the minute but the guy who checked them said he could feel or hear the value open as it should

[AlexD]

Based on the description it seems that the Heat Link is behaving as expected. It clicks when turning the heating or hot water on/off. That indicates that the relays inside are working as expected and point to something else in the system causing this behaviour. Generally such behaviour are common when there's something going on with a valve getting stuck but it could be something else as well.  

If you have a multimeter and are comfortable in performing some tests, I can send some instructions over email on how to perform a continuity test on the Heat Link. While it does not seem to be the Heat Link that's causing the behaviour, a continuity test will give us a definitive answer. If you want me to send it to the email associated with your account there, let me know. 

Also, if you have a preferred installer or electrician they can also perform the test. Though if they do or you do, it would be best if you reach out to us over our live phone line at +44(0) 808 169 2307 - available 0800 - 1900 GMT Monday to Friday and 0900 - 1700 Saturday and Sunday. This way my colleagues can provide assistance during the steps live and get in touch with our senior colleagues directly if needed. 

[AlexD]

Hi, I wanted to check in. Did you see my last message? Make sure to let me know if I can assist further.