First radiator come on when heating off

[diycooper]

I have a Vailliant eco tec pro 28 boiler and wireless salus controls. I have my stat set to snowflake which is just froast protection but sometime the radiator what I have goes warm even though the burner sign is not showing on stat. Can aayone help with this ?

thanks

 

[footprints]

Hi diycooper,
I'm a bit out of touch with current boilers, so I don't know your particular model, but most combi boilers need to "dump" any heat left in the heat exchanger when they turn off to prevent overheating when the water flow stops. A way to do this is via the heating circuit.

If you run the hot water and turn off, the excess heat is pushed around the heating circuit and a rad may heat up briefly. Chances are if you turn that one off the next in line will start doing it The longer the water is run the more noticable it will be, usually showering or running a bath causes it to be noticed.

Regards,
footprints

 

[dcawkwell]

Your diverter valve is starting to leak heat into the hot water system.

 

[diycooper]

Your diverter valve is starting to leak heat into the hot water system.

Would that explain a chuddering npise in boiler when heating on, only started this week. Got told it could be dirt in the fan ?

Thanks for reply

 

[diycooper]

Noticed again today now 2 radiators are coming on. If the diverter is leaking hot water into the system can this happen even if hot water has not been used ?

thanks