DIY Doctor UK DIY Forums

Hi there I've got a Valliant echo plus 28 combi boiler and what I've noticed is that when I set the thermostat target to say 20 it keeps on going( not everytime tho) I changed the stat to a nest thinking that might be the problem but noticed that again when I set it to 20 I would look an hour later (when feeling hot) and target temp changed to 24? Thanks

It would seem if you have changed thermostat that it's not the thermostat switching it on?

When the boiler is running when it should not is the nest thermostat orange or black. Nest display turns orange when there is a demand for heat, so should be easy to work out boiler or thermostat.

There is when using non combination boilers a anti legionnaires function with nest, it can be turned off, the idea is the water is every so often heated hot enough to kill bacteria and this does not show as heating being on.

Thanks for the reply. When the boiler is running when it shouldn't be then the nest is orange. I don't think it's the nest because it was happening with the old thermostat. It ran perfectly for 7 years and the boiler started to keep on running early this year. Wanted a nest and thought it would sort the problem out at the same time but still the boiler periodically keeps on heating until I intervene.

I would try the Nest help line as that should not happen. It is clearly the Nest calling for heat as it has gone orange, as to why not a clue.