Heating on constantly. Help!

[WinteryWonderland]

We had a new boiler last year and it's situated in the loft.
I understand frost protection etc but
now the cold snap has hit, the heating seems to be running constantly by itself 😳
The thermostat says 18 and its warm in the house. I lowered to 16, and the heating is still on 😧
Is it going to just stay on constantly during cold snaps?? That can't be right surely?
I want to use the log burner today to save on heating bills - but the heating just isn't going off.
Does anyone know? Is it frost protection/bcus boiler is in loft? I can't afford for the heating to be on constantly like this. Can anyone help?

Sounds like an issue then. Is there just one thermostat? There’s not a second thermostat somewhere chilly?

Hello I’m a heating engineer and happy to help. Can you tell me the make and model of boiler?

I never find boiler timers actually work when I want them to. We just turn ours on when we need to normally just 30 mins in the evening on cold days.

We had this problem once, house was unbearably hot even though it was snowing outside. It was a stuck valve (near the Megaflo).