Boiler not turning off

[Steve410651]

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

 

[Frank Nicklin]

When you installed the Nest did you re-wire or just swap the existing wires over. Are you using OpenTherm with the Nest as not sure if your Boiler supports it.

 

[Steve410651]

Had an electrician to do the nest but has I said I was getting the problem before I had nest installed

 

[Frank Nicklin]

Had an electrician to do the nest but has I said I was getting the problem before I had nest installed

So that would indicate a wiring issue with the stat or a faulty boiler controller. Did he re-wire the stat or use the existing wiring.

 

[Chalked]

Could have the stat link still in. Get your electrician back, or a gas safe engineer. As the case will need removing.

 

[Steve410651]

So that would indicate a wiring issue with the stat or a faulty boiler controller. Did he re-wire the stat or use the existing wiring.

He re-wired the stat

Could have the stat link still in. Get your electrician back, or a Registered Gas Engineer. As the case will need removing.

H thanks for replying but the heating system has been fine for the last 7 years, started playing up in the spring so changed over to nest and still having probs