New nest thermostat

[Jasmine4]

Hi I had a new boiler and nest controller put in last Thursday.  Since then on at least three occasions my boiler/heat pump have started up, go on for 5 mins and off for 5 mins and will continue to do so until I turn up the thermostat until the heating comes on.  It usually happens when I’ve not had the heating on for a while.

I don’t have auto schedule or pre heating on

i don’t have home/away on

I’ve done a factory reset

then on top of that a thermostat reset

I’ve turned the heating off but it still carried on till I turned the heating on

Ive contacted support but they took me through things I have done and then suggested I get a Google nest pro engineer in at my own expense.  I’ve only just got it so shouldn’t it be covered by warranty?

Any ideas what I can do?  I was so excited to get this system to monitor the heating and now I am worse off than when I had for 15 year old boiler

[CoolingWizard]

Who installed the “new boiler” and the new Nest thermostat. 

AC Cooling Wizard

[Jasmine4]

A gas/boiler engineer. I’ve had him back and he says it is the nest controller that is faulty not anything else.

[CoolingWizard]

What specific diagnostic testing did that engineer do when he came to the conclusion that it was the Nest thermostat?

AC Cooling Wizard

[Jasmine4]

He looked at the boiler, heat pump and hot water tank.  I didn’t see him do anything else.  He reset the nest controller back to factory and started again with it.  However 24 hours later it was doing it again.  He said I need to raise it with Google Nest.  
I’m having him back next week but I think he is still convinced it’s Nest.

[CoolingWizard]

When was the Nest purchased? If it is less than 12 months old, you might be able to get a warranty replacement.  

AC Cooling Wizard

[Jasmine4 · Accepted solution]

I now have the answer to my problem.  Although I thought it was the heating it actually was the hot water causing the issues.   Turns out there is a setting that defaults to enabled for bacteria prevention.  The description is:

Bacteria Prevention mode will activate if your domestic water hasn't been heated for at least two consecutive hours in the last 48 hours. This can happen if there is a gap of more than 48 hours in your hot water heating schedule or if you are away from home for longer than 48 hours.

I would never heat my water for 2 hours, not sure who would in a residential property and finding this information was incredibly difficult.  Nest support team never mentioned this function.  You can only find it on the controller not the app.

I’m just adding it here in case other people have a similar thing.  It took 3 weeks for me to find out I don’t want anyone else having to go through the hassle.