Room thermostat, what’s the point?

[Uncle Nick]

Hi all, as it’s starting to get chilly at night, we’re thinking of having the heating on at night… well the wife is.
Which led me to wonder whats the point of having a room stat when the radiators all have their own thermostat controls?
We currently have just a time controller for the heating, is there really any point in adding a room stat?

 

[ShaunCorbs]

Yes as the boiler could be heating away and all the trvs shut so wasting gas etc

That’s why you need to remove the trv where the room stat is etc

 

[Uncle Nick]

Yes as the boiler could be heating away and all the trvs shut so wasting gas etc

That’s why you need to remove the trv where the room stat is etc

Thanks for the reply.
The room stat is in the kitchen which has no radiators.
But I get what you mean.

 

[ShaunCorbs]

Thanks for the reply.
The room stat is in the kitchen which has no radiators.
But I get what you mean.

Is it fixed on the wall or movable eg wireless?

 

[Uncle Nick]

Is it fixed on the wall or movable eg wireless?

It’s fixed to the wall above the time controller.

 

[ShaunCorbs]

Weird place to put it normally kitchens keep warm with cooking etc

 

[Uncle Nick]

Weird place to put it normally kitchens keep warm with cooking etc

Yes I thought that but it was there when we bought the house over ten years ago.
The temperature in the kitchen must fluctuate more than other rooms as well due to cooking.

 

[Chuck]

The present arrangement is not satisfactory. It doesn't comply with building regulations, the house temperature will be uncontrolled and uncomfortable and it'll be wasting a lot of gas.

From the description, it should be straightforward to replace the thermostat in the kitchen with the receiver for a wireless programmer/thermostat. Locate the thermostat sender somewhere conventional, e.g. the hallway or a living/sitting room, where it will be influenced by a radiator that has had the TRV removed.

I'd think this simple change will give you a noticeable reduction in your gas consumption, my guess would be about 10%, possibly more. And the house will be much nicer to live in when it the cold weather comes.

 

[Uncle Nick]

The present arrangement is not satisfactory. It doesn't comply with building regulations, the house temperature will be uncontrolled and uncomfortable and it'll be wasting a lot of gas.

From the description, it should be straightforward to replace the thermostat in the kitchen with the receiver for a wireless programmer/thermostat. Locate the thermostat sender somewhere conventional, e.g. the hallway or a living/sitting room, where it will be influenced by a radiator that has had the TRV removed.

I'd think this simple change will give you a noticeable reduction in your gas consumption, my guess would be about 10%, possibly more. And the house will be much nicer to live in when it the cold weather comes.

Thanks for the detailed reply.
That would make a lot more sense, although the house has always been comfortable in winter and not used stupid amounts of fuel.
A saving on costs would be a great bonus though.

 

[gmartine]

Yes I thought that but it was there when we bought the house over ten years ago.
The temperature in the kitchen must fluctuate more than other rooms as well due to cooking.

...and it'll be colder at night.

 

[John.g]

I have mine, a fixed, digital type with 0.3C switching differential, in our combined dining/living room, set to 18C/19C during the day from 0700 to 1900 and normally 21.5C/22C from ~ 1900 to midnight, when/if we go out during the day we just press a button to change it to 17C.
All the remaining rads (also) have TRVs, kitchen set to give 19C, bedrooms 16/17C. Hallway 18C.

 

[Uncle Nick]

I have mine, a fixed, digital type with 0.3C switching differential, in our combined dining/living room, set to 18C/19C during the day from 0700 to 1900 and normally 21.5C/22C from ~ 1900 to midnight, when/if we go out during the day we just press a button to change it to 17C.
All the remaining rads (also) have TRVs, kitchen set to give 19C, bedrooms 16/17C. Hallway 18C.

Thanks for the reply.
Does those settings not mean that the boiler will be on, trying to heat to 18/19C or 21.5/22C but the radiators won’t be heating as they’re set at 16/17C?

 

[John.g]

No, the boiler has its own thermostat, set (mine) to 70C, so once the boiler is switched on from the roomstat then it will control the boiler/system water to 70C, the TRVs will control the flow rhrough their respective rads to give their requiredroom temperatures, obviously if the dining/living room roomstat is satisfied then the boiler switches off but because the settings are higher than the other room TRVs then generally these rooms are satisfied before the living/dining room is reached, I have the two rads in the living/dining rooms throttled/balanced as well which helps to achieve this, it works quite well. I would definitely though suggest installing a digital roomstat as it gives very tight control but I wouldn't go for anything too fancy like one with TPI control except that you can disable this feature.
As I said, mine has differential temperature control (set to 0.3C) so if the roomstat temp setpoint is 20C then it should swith off at 20C and switch back in at 19.7C but I've noticed that when the rooms are heated up that it seems to switch in at 19.9/19.8ish and switch off at 20C. I would think that all the well known manufacturers make this type, mine is a (less well known) FantiniCosmi.

 

[Uncle Nick]

No, the boiler has its own thermostat, set (mine) to 70C, so once the boiler is switched on from the roomstat then it will control the boiler/system water to 70C, the TRVs will control the flow rhrough their respective rads to give their requiredroom temperatures, obviously if the dining/living room roomstat is satisfied then the boiler switches off but because the settings are higher than the other room TRVs then generally these rooms are satisfied before the living/dining room is reached, I have the two rads in the living/dining rooms throttled/balanced as well which helps to achieve this, it works quite well. I would definitely though suggest installing a digital roomstat as it gives very tight control but I wouldn't go for anything too fancy like one with TPI control except that you can disable this feature.
As I said, mine has differential temperature control (set to 0.3C) so if the roomstat temp setpoint is 20C then it should swith off at 20C and switch back in at 19.7C but I've noticed that when the rooms are heated up that it seems to switch in at 19.9/19.8ish and switch off at 20C. I would think that all the well known manufacturers make this type, mine is a (less well known) FantiniCosmi.

Thanks for the detailed reply.
I think I understand how it’s meant to work now.
Looks like I’d better get a room stat fitted before the cold weather!