Boiler frost stat

Hoploz

Having been worrying there's a fault with the boiler in my new house I have suddenly realised a frost thermostat is the reason it keeps staying on when the timer is off.

Does it sound normal that the boiler fires and the hot water comes on, not the heating? It seems to remain on until the next timer session tells it to go off. From what I have read a frost stat should turn the heating on and go off once the room the boiler is in gets to a certain temp? The manual here says it fires when the boiler water goes below 6 degrees and stays on until it reaches 16. It's an old boiler and I'm still not convinced it is working appropriately - ie the boiler is heating the water all night long till next morning. Surely the water temp would have reached 16 without it staying on all night?

Sorry, I'm a bit confused ... And skint so not wanting to ask my plumber if it sounds right!

Thanks.

Jonesya

Is your frost stat a room/air thermostat or a pipe thermostat? Or both? Or is it internal to the boiler? Where's it located?

I've got a boiler in the garage and on frosty nights the room/air frost thermostat would keep it running a lot of the time because the boiler didn't give off enough heat to warm up the garage to get the thermostat to switch off, so it would stay on for very long periods, just circulating the water and firing occassionally. Although I think mine was heating the central heating.

I guess the thing to check is, how hot is the room or pipework getting and what is the thermostat set to? Should it be cutting out?

Similar to yourself I thought this was inefficient and after doing some research i added a pipe thermostat in series with the air frost stat so it now cuts out once cold return pipework gets up to a safe temperature.

Hoploz

Mine is built in to the boiler. The boiler is inside the house. I have no idea whether there is a pipe stat, or whether one is needed ... I will ask the plumber when I next see him I think, now I have worked half of it out!

I am just really conscious of the cost as we have moved to a bigger house and are spending a fortune on energy bills, I'm going round turning off every unwanted lightbulb, then noticing the boiler is firing all night long! Am hoping as its only the water it seems to heat, that it will be cheaper than running the radiators