Heating OFF/Water OFF - BUT Boiler ON

[Sam05]

Hi there, 

Whilst we love our NEST we appear to have issues with it which we can't seem resolve.

Having reset the app and auto scheduler to get it to operate like a normal thermostat it is still switching the heating/or hot water on when it is not being asked to do so!?

Have spoken with the plumber who says that the boiler will not come on unless it is called to do so by the thermostat and says it is not the boiler but our NEST

I wondered if anyone can shed light, is it the NEST?

Thanks in advance 

[CoolingWizard]

Do you have a Volt Ohm Meter? If the plumber is saying the nest is calling for heat, have him show you with a volt ohm meter, the call for heat at the heating system controller.  There should be approximately 24Volts AC a the heating system if there is a call for heat.  So, you must have two separate cables coming to the thermostat. One from the heating system and one from the Air Conditioning system? 

[AlexD]

Thank you for reaching out to us here @Sam05 . I am sorry to hear you are facing this behavior and would be happy to try and assist. 

Firstly, how long has the thermostat been installed for and when did you first notice this behavior from it?

Also, when it happens to turn the heating on, does the display go orange and shows it is heating, or is ti black and shows that it should be off? 

Thank you for your input @CoolingWizard . But in this case, since it is heating and hot water control, it is an EU style thermostat and not the US one. It is installed differently and has some different functions. Thank you for your enthusiasm and suggestions. 

[Sam05]

Many thanks for your advice and having googled a little further and read a bit more it would appear we have found the culprit! We've watched it for the past week to see if the boiler requested but nothing and also on viewing gas usage we finally found the issue. The legionella setting was the culprit and not the easiest to find or to figure out!

Fingers crossed we have now solved our issue and many thanks for your assistance. 

[DragosC]

That's great news. Thanks for letting me know. I'll have to close this thread. Should anything else come up, please open another thread and we'll take it from there. Have a good one and stay safe!

[DragosC]

Hi there. I'm just following up on our last message. Do you still need our help? Keep us posted.