Boiler turning on when Nest says heating & water heater OFF!

ImranQ

Hi All,
We had a Nest installed at the end of April.

Currently we have a problem where the boiler is turning on even though the Nest is saying heating and hot water is off.

I have turned off eco mode and auto schedule/learning and everything is on a manual schedule. So even though currently there is no schedule active the boiler is currently firing.

We have been having this problem for a little while and I reported the problem to Nest a couple of weeks ago. They came out last week and changed the controller but the problem seems to be still there as the boiler seems to have kicked on as I write this post!

Anyone had this problem or heard of a problem like this?

Regards,
Imran

dj1471

Combi boiler? When you say it's coming on, is the heating coming on?

Are you sure the boiler isn't maintaining a supply of hot water? Mine does that if I don't put it in eco mode.

ImranQ

Hi,
Thanks for replying.

We have a normal boiler not a combi. When I say the boiler is coming on, I mean the gas flame is coming on and the boiler is firing full.

I have no clue whether its the hot water or the heating. However, I checked the radiators and they seem to be cold. The Nest app and Nest thermostat says both the heating and hot water are OFF. Also I know something is on as the gas meter is running furiously!

I'm not sure that the boiler should be turning on. When we had the normal programmer, the boiler would not come on until either the heating or hot water were explicitly turned on using the programmer by using the manual mode or the timer.
Regards,
Imran

Alex1983

I would be suspicious off the zone valve being faulty and telling the boiler you want heat even when the nest is OFF. If the radiators are cold it's likely to be the hot water valve faulty.

ImranQ

Alex1983 wrote: »

I would be suspicious off the zone valve being faulty and telling the boiler you want heat even when the nest is OFF. If the radiators are cold it's likely to be the hot water valve faulty.

Thanks Alex, tho we never had this problem when we had the normal programmer. Why now with the Nest?? Is there something particular about the way the nest works?

djp64

I have a normal boiler too and had the same problem. Have you turned off the legionnaires setting? I can't remember where it is but with this on it will heat the hot water periodically to ensure that you don't get legionnaires disease. I turned it off and no longer have the problem.

Debbie

ImranQ

djp64 wrote: »

I have a normal boiler too and had the same problem. Have you turned off the legionnaires setting? I can't remember where it is but with this on it will heat the hot water periodically to ensure that you don't get legionnaires disease. I turned it off and no longer have the problem.

Debbie

Thanks Debbie. I haven't seen that setting but I'll try and find it. Someone else on another forum suggested to have the boiler on for more than two hours a day for the exact same reason due to the legionnaires internal setting in the Nest.
Would you be able to tell me where your setting is located? i.e. what menus do you go through to get to it? Thank-you.

ImranQ

I just saw these links:

www boards ie/ttfthread/2057814593/2
nest com/uk/support/article/How-does-the-Nest-Thermostat-help-prevent-Legionella-bacteria

Perhaps this is the answer to the 'problem'. I am surprised that the Nest support haven't told me about this if it is actually a 'feature'!

Alex1983

How often and how long is it firing for?

Jojomissy

We had the same issue and had the zone valve swapped. It did turn out to be the "safety feature" on NEST after all.

This feature was switched on via an update but without informing NEST customers. If your water is not heated for 2 hrs a day it clicks in unless you disable it.

We were only heating the water for 1.5 hours hence the boiler firing up randomly. It took me ages to solve it as it was shortly after the update and there was not a lot on the web regarding it.

Xx

roger-w5

There are a lot of 'depends on this,depends on that', first do you have any maintenance cover or insurance for the boiler-heating system ?.

Could be a few reasons why your boiler fires up when there is no demand,we dont know which components have been used or what type of system you have.installations vary.
Assuming its installed correctly it should be a component fault.Its an easy job for a heating technician or are you going to try a diy fix ?.