Correct position of thermostat for central heating

[Mike P]

just moved to a "new" house.

Rads have TRV's ..... There is a wall thermostat in the hall at bottom of the stairs ... and NO radiator.

So ......... if I set the hall thermostat to 20deg and I wish the other rooms to be the same temperature (20 deg) with doors shut, I can control rooms with TRV's .... right ?

So what happens when the rooms reach 20deg? I assume the TRV's shut the water feed to the rads.

So what is happening in the hall and the upstairs landing space etc ? Hot air rises so will the boiler keep grinding away until it is 20deg is reached at the bottom of the stairs from the top ? I do not really want it that warm up there.

If I set the thermostat lower .... then the rooms will not reach 20deg ... methinks.

Is the thermostat in the right place ?

Mike P

Mike P

[Dave Baker]

Clearly not. It should be in the main room whose temperature you want to control, usually the lounge. You'd also want one rad in there without a TRV to act as the master rad.

[Jim Alexander]

No, because the hall is unheated. If you set the hall thermostat to 16deg say the rooms would *probably* get to TRV temp because there will be temperature gradient between the hall and each room. The hall stat is really just a crude way of reducing boiler cycling.

There is not a straightforward answer to your question but its a common arrangemnet. To control all rooms by TRV requires the boiler to be on permanently which leads to wasteful cycling. Possibly you are suggesting the stat should be the living room. That gives you good control of living room temperature but unsatisfactory control of the heat to the other rooms. On balance the hall is as good a place as any for a simple system. If its not a programmeable stat consider upgrading to one.

Jim A

[John]

I would have thought that a Wireless Stat would be the solution then it can easily be put in the lounge without disturbing the wiring.

[Mike P]

.. >

.. >> Rads have TRV's ..... There is a wall thermostat in the hall at bottom .. >> of the stairs ... and NO radiator. .. >>

.. >> So ......... if I set the hall thermostat to 20deg and I wish the .. >> other rooms to be the same temperature (20 deg) with doors shut, I can .. >> control rooms with TRV's .... right ? .. >>

.. >> So what happens when the rooms reach 20deg? I assume the TRV's shut .. >> the water feed to the rads. .. >>

.. >> So what is happening in the hall and the upstairs landing space etc ? .. >> Hot air rises so will the boiler keep grinding away until it is 20deg .. >> is reached at the bottom of the stairs from the top ? I do not really .. >> want it that warm up there. .. >>

.. >> If I set the thermostat lower .... then the rooms will not reach 20deg .. >> ... methinks. .. >>

.. >> Is the thermostat in the right place ? .. >

.. >Clearly not. It should be in the main room whose temperature you want to .. >control, usually the lounge. You'd also want one rad in there without a TRV .. >to act as the master rad.

Thanx .... master rad is in the bathroom

Mike P

[Vass]

seen the price of those things? jeeez

[Andy Hall]

What about the cost of redecorating and of your time?

[Mike P]

.. >>

.. >>

.. >>

.. >I would have thought that a Wireless Stat would be the solution then it can .. >easily be put in the lounge without disturbing the wiring. .. >

We had one of those for the Woecester boiler at my last place. It was brilliant. Just carried it about where we were most at.

Mike P

[robert]

And if you dont have a main room the single thermostat will be a pain if used "correctly". A bit of sun on one side of the house and a cold wind blowing on the other can also play havoc with this type of control. Not sure what the alternatives are if you are trying to minimise boiler cycling ?? Robert

[jal]

Surely it doesn't matter _where_ the thermostat is?

Ours is set at 17 degrees (it happens to be in a corner of the dining room). We have found - by experimentation - that at that temperature, everywhere else is reasonably comfortable. If ever we find we're cold in the lounge, we walk to the dining room and tweak the stat up a degree. It's no big deal, and the whole arrangement costs us ... nothing.

John

[Ed Sirett]

I'm using these regularly now as they are only £40 more than a wired unit. It allows the user the possibility to experiment to find the best place for the control. Then, later, if it's practical, a wired unit can be substituted.

[David Hansen]

On Sun, 30 Sep 2007 15:01:21 +0100 someone who may be Mike P wrote this:-

Almost certainly not.

Such a thermostat should be placed in a location which reflects the external temperature, will not be influenced by internal heat gains and will cool down most rapidly when heating is off.

An ideal place is a north facing bedroom. Living rooms are best avoided as they may have supplementary heating, kitchens are best avoided as they have cooking equipment in them which (one hopes) will give off heat.

[Roger Mills]

I think that this may have been asked already, but what is the legality and practicality of putting the stat in a bathroom?

If it's switching mains, is it ok in some zones but not others? Will it be adversely affected by steam?

If it's not switching mains - e.g. the sender part of a wireless stat - presumably it's legally ok in a bathroom? But will the steam foul up its electronics?

[Derek Geldard]

Yes but rather contentious amongst the older generation who had central heating "put in" in the late '60s

Me : "Why did you have the thermostat placed just inside the front door.

F.I.L. : It's the coldest place in the house.

Me : But the all the radiators in the house will come on when you open the front door.

USW. USW.

Being quite serious, that's outside, Not that mine is outside, mine is in the lounge but the only heat input apart from a couple of radiators with lockshield valves. is the TV which is on constantly so gets compensated for when the radiators are balanced, and the heat output of human beings. if they affect the demand on the boiler at least that's where they are.

The net result is not bad except when SWMBO starts steam ironing in there whilst watching TV. Then the heating to the entire house shuts down. :-((

DG

[David Hansen]

On Tue, 2 Oct 2007 17:54:20 +0100 someone who may be "Roger Mills" wrote this:-

It is just like any other electrical switch in a bathroom. In Ye Olden Days such a switch could be installed, provided it was not within reach of someone using a (fixed, in Ye Really Olden Days) bath or shower. In new money much the same thing applies, though this is now expressed in terms of zones.

Probably depends on design. My internal frost stat happens to be in a bathroom, as it is the place which loses heat most rapidly and has not been affected.

If the stat was controlling the heating then it will be affected by heat gains in the bathroom, from baths and showers being taken in particular.

I suppose condensation might bridge some bits of a PCB. Suitable conditions are usually stated in the instruction booklet.

[David Hansen]

On Tue, 02 Oct 2007 18:22:22 +0100 someone who may be Derek Geldard wrote this:-

It is indeed. If one has a system where weather compensation makes sense then that is a good place for one of the sensors.

She does too much ironing:-) Tell her to relax.

[Pete C]

I'd also look at a differential bypass valve, and put a thermostat on that too.

Or have it across the TMV in the room the thermostat is in.

cheers, Pete.

[RobertL]

One could wire several thermostats in parallel, located in different partsof the house. The boiler is on if any of the thermostats is demanding heat but the TRVs actually control the temperatures.

The thermostats could each be the clever ones with electronic timers included.

Robert

[Roger Mills]

Yes, I'd already wondered about doing that, and I don't see why it shouldn't work. What I have in mind is a fixed (programmable) stat in parallel with a wireless programmable stat. The wireless stat could be moved from room to room depending on priorities at any one time.

[Ed Sirett]

Most likely a normal mains wired themrostat/programmer is rated at IP22 so not suitable for a bathroom (maybe zone 3?). It is however a highly impractical suggestion even if using a wireless unit as the bathroom temperature is volatile and unrepresentative of the house as a whole.