Nest Thermostat 3rd Generation - Downstairs Heating activating when i boost the hot water

[MikeOHall]

**Help needed**

Electrician installed two nest thermostats:

- 1 - controls downstairs heating zone & hot water

- 2 - controls upstairs heating zone

No issues previous to the nest installation - and now the downstairs heating zone activates (radiators heat up) whenever i boost or schedule the hot water. 

Can anyone provide a solution or insight on why this is happening. 

Thanks in advance. 

[Frustratedddd]

Are you in the UK?

What did the electrician say when you asked him to come back and look at the issue, what did they find that might be the issue?

[MikeOHall]

Based in Ireland. Electrician coming back next week with plumber to see what the solution may be

[Frustratedddd]

OK, sounds like incorrect wiring or motorised valve issue.  Hope you get sorted.