Works fine during the day, i.e. set the thermostat and all is well and good. During the night? Bastard thing has a mind of it’s own. Thermostat is well down but the boiler will fires up, radiators blasting regardless of the temp set on the thermostat. Installer has been slightly less than useful so I thought I’d consult the oracle.

Anyone had similar experiences or can provide advice?

Cheers.

Could it be to do with the frost protection ?

Yup, sounds like frost protection to me too.

Agree with the above, but ours doesn’t heat the radiator when it kicks in, although I often wish it did!

Yeah, I thought frost protection but surely it should only fire up to keep at a minimum temperature and it certainly shouldn’t have the radiators blazing like the fires of Hades.

Where is boiler fitted ?would it be cold enough to activate frost stat ,modern combi,s have a preheat for hot water which fires once and hour to heat boiler, couple this with faulty diverter valve and hey presto hot rads all night long

Peasant. Thanks for that. It seems to make sense but why does it only happen at night?

Boiler is in loft and it has been cold enough in the daytime for frost activation but it slavishly adheres to the thermostat between 06:00 and 00:00. The thermostat is a wireless one. Could we have interference from another source?