Can't get a handle on my newish room thermostat

[CoolCadbury]

The old room thermostat stopped communicating with the boiler last year so this spring we had a new thermostat fitted.

The problem is that the frost protection is set at 5 degree celsius so last night the heating came on in the middle of the night! [shocked] I can just see it coming on all the time in the night during the cold winter months and the cost of heating going up astronomically.

Is there any way that I can override the frost protection temperature of 5C or change it to come on at zero degree? I know I can just turn it off and switch it in the morning when we get up and that is fine for now but I don't fancy doing that in the middle of the winter.

If anyone knows anything about this, it would be greatly appreciated. It's a Siemens RDJ10RF/SET-GB.

It works out cheaper, honestly, to rumble along with a reasonable minimum, than only putting the heating on when you're unbearably cold. Our gas bill went down when we installed a similar system even though the heating was on more often and the house was warmer ...

Persevere! Don't let your walls get cold.

If the room temperature drops to 5C, which is very cold for an inhabited room, the boiler will turn on to warm it, thethen go off.

Or is your boiler in a shed, outbuilding or loft? In which case the frost stat warms the boiler and pipes.

Which country are you in?

All thermostats work slightly differently regarding their setting up. Which one do you have?

For instance if it's a. Honeywell you just need to set the off temperature at lower than 5degrees. The thermostat will only ask the heating to come on if that temperature is reached.

However as pigletjohn says it's very unusual for a room in a house to get that cold, so perhaps your boiler is external or in a garage and therefore the frost stat is bringing it on to protect the boiler. If this is the case it won't be on for long, just enough to stop the boiler freezing therefore won't be using much fuel.

pigletjohn I am in the UK! The room thermostat is at the top of the stairs, and the receiver is only a few metres away in a cupboard (with the boiler).

whatdoiknow unfortunately it cant be changed in the sense it cant go lower than 5 degrees but can go higher than 5 degrees. It's a Siemens one.

Any chance it could be faulty?

Hang on, it thinks it was below 5? indoors last night? Must be faulty!

mrshathaway, thank you for telling me about your experience - it feels more reassuring. It feels so counter-intuitive for it to come on at night when in bed. I can understand it in deepest winter but can't see why it would come on in early autumn.

it is more usual to put the thermostat in the room which you use most (but away from fires, cookers, sunny windows, other sources of heat)

It must be in a room with a radiator.

Ah, pigletjohn I think it can be moved about so I will see if I can detach it from the wall and put it in the living room.