Valiant Ecotec 831 combi heating turns on random

[goooba769]

Got the Ecotec combi 831 and lately I have started to hear the heating kick in even though temp is set to 19C and its reading 23C!
Anyone come across this?

Wondering if the Honeywell thermostat/programmer is faulty or could it be a faulty sensor on boiler? Recall reading boiling has a low temp sensor to kick the heating on and wondered if that was faulty.

 

[muggles]

Do you have hot water preheat turned on?

 

[goooba769]

Yes it's turned on. I've just turned it off to see if that improves.

Do you think that could be impacting? Surely that's on the hot water circuit rather than the heating circuit?

 

[muggles]

It is on the hot water circuit, but if the diverter valve is stuck partly open it'll heat up the radiators. Run a hot tap and put your hand on the heating flow off the boiler. Does it get warm?

 

[dilalio]

Can you select "off" for the heating, rather than just relying on a low stat temp acting as an analogue "off"?
When you say you can hear the heating "kick in", do you mean you can hear the boiler fire without a tap running? If so, a smuggled said, this could be the preheat which is for the HW but the diverter is letting by to the CH circuit. Running a hot tap and feeling the rad nearest the boiler will help test for this.

 

[goooba769]

Cheers both looks like the central heating pipe starts to get warm when I run the hot water so I suspect the divert valve