3rd generation nest thermostat is not heating up or warming up the water

[AnastasiaT]

Hi all. I just got the Nest 3rd generation thermostat. I had an engineer to do this. 1st day it was working fine. 2nd day it got disconnected from the heatlink. I spoke to Google and I was able to get the thermostat connected to the heatlink. Since then the thermostat cannot heat up the radiators or warm up the water. I can only do this manually by clicking the button on the heatlink. I can't find an answer via Google support. When I turn on the heating from the thermostat I can hear the clicking on the heatlink but nothing happens. The same with the water. I had an old system before which had no thermostat so we were able to control heating manually but also set up when the heat to run or when to have hot water. Anyone else had the same issue?

[TudorL]

Hi there @AnastasiaT and thanks for reaching out to us. I'm really sorry about this but I'll do my best to assist you with this issue. So, just to confirm, if you press on the button on the Heat Link, that is turning on the Manual mode, the heating is activated and the hot water as well, right? But if you want to activate each of them separately, none of them activate? 

[AnastasiaT]

Thank you for jumping on this. Yes that's correct. I can hear the heatlink clicking but nothing happens

[TudorL]

No worries at all, it's my pleasure to assist you. I'll need you to answer some quick questions, so I can gather some extra info: 

1. Do you have a system boiler or a combi boiler?

2. Did the engineer perform any actions on the boiler or valves - maintenance, changes in the system? 

[AnastasiaT]

1) System boiler

2) no changes in the system. when Nest was installed by the engineer it was working fine. It all started the next day. The only thing we did in the meantime is to download the app to our mobiles

[TudorL]

Understood. And the LED light on the Heat Link is green, right? 

[AnastasiaT]

Correct

[AnastasiaT]

Also when we turn the heat on from the thermostat, the boiler starts burning but it's not heating the radiators or the water tank. We just burn fuel.

[TudorL]

Thank you for all the information. Considering all the information I have, the situation is the following: the communication between the thermostat display and the Heat Link works properly, as well as the communication between the Heat Link and the boiler, since the boiler fires up when receives the signal. It's most likely that your heating system is a Y-plan, consisting of a two-port valve, which is stuck and it doesn't allow the water to flow through the entire system. In this kind of situation, we recommend you to call in an installer and check in the valves. 

[AnastasiaT]

Sure I can do this. A couple of questions. If the valves are blocked why are they working when on manual mode? Also how come and it was working fine on the 1st day and since the thermostat got disconnected it's not working?

[AnastasiaT]

Good morning. I have the engineer over. There is no Y-valve and he says it's an S system the one we have. Any suggestions?

[AlexD]

Thanks for the update. In the case of the Y plan especially activating both heating and hot water, like using manual mode, at once can make it open at both ends and have it work. While just operating one, may not be able to activate while the other side works as expected, heating or hot water depending on the situation. 

If you have the engineer over I would recommend you have him check the whole system. What would be best, for the Heat Link side, is to perform a continuity test on all terminals. I can email you the instructions for this, if it would be ok if I reached out to the email associated with your account here, or you can get in touch over our live chat or phone line with the installer there and my colleagues can walk them through the whole testing process. You can find all our contact details here. 

[UanaC]

Hello there! Just checking in with you. Did you see my colleague's previous message?

[LarisaL]

Hi there! Since we haven't heard from you in a while, I'll be locking this thread. If you have any new issues, updates or just a discussion topic, feel free to start a new thread in the community. 

Thanks, Larisa.