Lost control of thermostat at night

[Gilly12]

We recently had a new boiler installed and a Nest thermostat. It’s worked for 3 weeks but two nights ago the heating was on even though the thermostat said it wasn’t. It became controllable again during the day. This has happened for three nights in a row. It’s as if someone else has control of the thermostat at night and is controlling our heating but not during the day!

There is no logo in the middle of our Heatlink, could it be a fake?

[AlexD]

Thanks for reaching out to us here @Gilly12 . I would be happy to try and assist. 

Newer units, since the merger of Nest and Google, may not have Nest in the middle on the button, that is perfectly normal. 

Do you have a system boiler at the location with a separate hot water tank, so you have both heating and hot water control on the thermostat or something like a combi boiler and you only control the heating from the thermostat? 

[Gilly12]

Dear Alex,

Thanks for replying. We have just had a new Veissmann boiler fitted which I think is a combi-boiler. The heating engineers fitted the Nest system as part of the job. I have a Nest thermostat in my business premises and never experienced anything like this with it.

Our heating is on almost constantly at the moment and we can’t switch it off. We have just had to turn off all the radiators except the ones in our hallway that we can’t switch off. We are too hot at night!!!

I held the button on theHeat link in to reset it but the same thing happened again.

Any help would be much appreciated.

Kind regards

Gillian 

[AlexD]

Thanks for the details. Let us check a few things. With the Nest app go next to the Heat Link, if you have the thermostat added to the app. Turn up the temperature until the display goes orange and listen for a clicking noise from the Heat Link, also see if the boiler is on or off after. It should be making noise or have some status LED or display that may show if it is active. Then turn the temperature down when standing next to the Heat Link and listen for a clicking noise again. 

Let me know if it clicked in both of these cases, this way we can check the internal relay behavior and let me know what the boiler is doing, if it is on or off. 

[Gilly12]

The heat link clicked both when switched on and switched off but the boiler stayed on all the time and won’t go off

[AlexD]

Based on the clicks that would indicate that the Heat Link is working as expected. The command from the app is sent to the display, the display passes it on to the Heat Link and it changes the state of the relay with an audible click. 

Do you happen to have a separate programmers in the boiler or separate from the boiler that could influence the system?

[Gilly12]

The boiler is programmable but we haven’t touched it since it was installed by the heating engineers so don’t understand why it changed three nights ago to being uncontrollable!

[Vladut]

That would be a strange behavior indeed. Can you send us a picture of your schedule? 

[Gilly12]

[Gilly12]

Right now it’s at 18 and the radiators are now cooling down which is fine but last night the heating was on most of the night again keeping the temp at 19 even though it was set at 14.5.

[Vladut]

Thank you so much. That also can mean that the True Radiant Feature might be enabled. Can you please go to the thermostat in Settings>Nest Sense>True Radiant and set it to off?

[Gilly12]

I actually did that yesterday evening. 😕

[Vladut]

Do you remember if yesterday evening if the color of the thermostat was orange or black?

[Gilly12]

It was black even though heating on 

[Vladut]

That is a strange behavior indeed. In this situation the thermostat seems to behave accordingly. The next thing to be checked are the wiring and the boiler itself. And for that you'll need an installer. Do you have the means to contact one?

[Gilly12]

Yes, we have someone coming out on Tuesday, unless we can fix it before then! It feels like someone else is controlling our heating !!! Hopefully get to the bottom of it next week then !

[Vladut]

Great. Thank you so much! If the heating was on and the thermostat was black that might imply some wiring and boiler to be checked out. And definitely you'll need an installer for that.

[UanaC]

Hello there! Any updates on the matter? 

[AlexD]

Hey there, I haven't heard from you in a while so 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, AlexD.