thermostats

robbomc

Hi Bit of a stupid question but hear goes.

Got a new heating system 18 months a go. Combi, trvs, cavity, loft insulation etc.

Where would you all suggest we put the themostatic controls? We have them set at 10.00min and 25.00 max.

The controls are in the passage and rarely get to 18.00 degrees when heating is on. if goes above that then we tend to turn the heating off as its more than comfortable. But upstairs its about 20-21 in the babys room.

Would you suggest that the thermo should be upstairs where warmer or downstairs in probably coldest part in house.

Magentasue

Ours is in the hall. At 16deg it's effectively off so that's what it's set to at night. Day time 18deg if I'm in and sitting around (aka working from home) and up to 20deg evening.

Cardew

You have described the problem we all face in situating a wall thermostat. No matter where it is situated cold hall, warm living room etc it is a compromise.

My solution, and that of many others is to have the thermostat up to maximum and regulate the temperature of rooms purely using the TRVs.

Many older systems do not even have a thermostat.

The ideal solution is to have a controller that can set different temperatures in different zones of the house.

Magentasue

Cardew wrote: »

The ideal solution is to have a controller that can set different temperatures in different zones of the house.

Yes, should add that upstairs rads are on 3 (goes up to 5) as is kitchen. Living rooms and bathroom are on 5. Will probably turn bedrooms and kitchen down further when it warms up and we only need a bit of heating in the evenings.

Premier_2

robbomc wrote: »

Hi Bit of a stupid question but hear goes.

Got a new heating system 18 months a go. Combi, trvs, cavity, loft insulation etc.

Where would you all suggest we put the themostatic controls? We have them set at 10.00min and 25.00 max.

The controls are in the passage and rarely get to 18.00 degrees when heating is on. if goes above that then we tend to turn the heating off as its more than comfortable. But upstairs its about 20-21 in the babys room.

Would you suggest that the thermo should be upstairs where warmer or downstairs in probably coldest part in house.

The general thermostat is ideally located in your main living room - so that the temperature where you live most (when awake) is maintained at the desired temperature. However, it does seem common for thermostats to be located in colder hallways (perhaps for asthetic purposes) and then temperature control is more difficult.

Because warm air rises, the thermostat should be located on the ground floor.

Also with a correctly balanced heating system (radiator sizing & flow rates) a
lower temperature should be attainable in the bedrooms compared to the living room.
TRV's in the bedrooms will aide this further.

Note, it is not advisable to have TRVs on all radiators in the property. A few problems can arise if you do.
(1) If the TRV is set too low in the room that the general thermostat is located, then it is possible with the general thermostat set too high for the heating never to attain the desired temperature as set on the general thermoststat. This leaves the possibility of the boiler continually running and so costing money.
(2) If all TRVs are set too low, that can restrict water flow within the system (since all radiators could be effectively off) and could cause your boiler to fail due to overheating. (Return temperature too high)

robbomc

cheers guys.

All 17 rads have trvs set on 3.

Boiler temp conrols go from 1 - 9 and we have it on 6 i guess mid range is that resonable?

Not to impressed about trvs as radiators seem to be bounceing with the heat but they dont seem to turn them off does that indicate a problem with fiiting.

Can they be fitted wrong?

Due a bill and i guess its going to be a big one but i guess not alone there.

Thanks

Cardew

Premier wrote: »

Note, it is not advisable to have TRVs on all radiators in the property. A few problems can arise if you do.
(1) If the TRV is set too low in the room that the general thermostat is located, then it is possible with the general thermostat set too high for the heating never to attain the desired temperature as set on the general thermoststat. This leaves the possibility of the boiler continually running and so costing money.
(2) If all TRVs are set too low, that can restrict water flow within the system (since all radiators could be effectively off) and could cause your boiler to fail due to overheating. (Return temperature too high)

Premier,
Re (1)
I have my thermostat set way above the temperature in the hall will ever achieve.

The boiler will not continually run, as like any system, it shuts off when the water temperature in the system reaches the temperature set on the boiler.

The wall thermostat shuts off the pump when the room temperature is reached, and there is no circulation of water.

Re (2)

On the subject of TRVs, it was certainly the case that older CH systems required one radiator to not have a TRV fitted for the reasons you explain.

I have TRVs on all radiators.

However most modern(last 20 years) have a Automatic bypass(pressure balancing) valve(ABV) so it is OK to have TRVs on all radiators - I mention that in case someone gets worried.

Premier_2

@robbomc

I would open fully the TRVs of any radiators in the hallway where the main thermostat is located.

At present the boiler is being controlled by the main thermostat, but you are hindering the temperature rising by restricting the heat output of those radiators.

Cardew

robbomc wrote: »

cheers guys.

All 17 rads have trvs set on 3.

Boiler temp conrols go from 1 - 9 and we have it on 6 i guess mid range is that resonable?

Not to impressed about trvs as radiators seem to be bounceing with the heat but they dont seem to turn them off does that indicate a problem with fiiting.

Can they be fitted wrong?

Due a bill and i guess its going to be a big one but i guess not alone there.

Thanks

See above about TRVs on all radiators - it is normal now.

Yes TRV's can be fitted incorrectly.

If you unscrew one using the knurled nut(nothing will leak) you will see that it operates a plunger. This has a stiff spring - up is on and pushed down is off.
It is important to have the top of the TRV correctly located - there is a slot.

You can find the instructions on the internet.

Premier_2

Cardew wrote: »

Premier,
Re (1)
I have my thermostat set way above the temperature in the hall will ever achieve.

The boiler will not continually run, as like any system, it shuts off when the water temperature in the system reaches the temperature set on the boiler. ...

Yes, its a safety device built into the boiler to prevent damage when the return temperature is too high.

But just like in a car with a rev limiter which shouldn't be relied upon to prevent the engine being damaged, the safety systems of the boiler shouldn't be relied upon to prevent you damaging it.
If you have your heating system correctly balanced, (and it was correctly designed in the first instance) you should be able to set the controls to avoid the safety system cutting in to prevent damage.

Cardew wrote: »

The wall thermostat shuts off the pump when the room temperature is reached, and there is no circulation of water.

That's the way it should work, not with the boiler cutting out because the return is too hot. (or the flow/return difference too small)

robbomc

thanks again

I think it is warm enough in the house so if the thermo on the boiler is at six and rads at 3 assumeing they are fitted correctly and the house is comfortable is this the most efficant method of heating.

Or should we turn everything up to 9 on boiler and 5 on the rads and set the thermo in the hall at say max 20 and let it cut out when that temp is reached.

Is this the most fuel efficant way or is there no such thing??

Can I also assume that the bigger the system the more gas you use or is not as simple as that and its down to efficancy of boiler, system, design etc.

Or is it back to lower temperature for longer or higher temp for less??