Best Way To Control Central Heating

[CW1]

Hi,

Have put the gas central heating on for the 1st time since I moved, & my neighbour & I were discussing what seems to be different ways of controlling the temperature. He (& the people here before me) never use[d] the thermostat, just turned it on via the boiler (the latter I think because I found out the thermostat was faulty !).

We run off calor gas bottles so he has his heating for about 30mins a day & that's enough. If anything, he said his radiators get too hot. He doesn't have trvs. I do, & they're at max, but I've noticed on the BAXI boiler there's a temperature with a radiator symbol. His was set at 60° but he's turned it down to 40°. Mine was 30° (default, I guess) but have turned it up to 40°. Does that have any bearing on the room temperatures ? My [new] thermostat in the hall is set to 15° but my heating's been on about an hour now & the radiators are barely warm. The rads may need bleeding I guess, but how does the temp on the boiler affect anything ?

[Old_Geezer]

I always put the main thermostat on max. Different rooms need different heat so a single sensor is no use to man nor beast. I use the controls on each rad to set it correctly for the location.

[CW1]

Old_Geezer, I agree with your logic but wouldn't the boiler just stay on then, trying to get the temperature around the thermostat up to max ?

Would like to know the relevance of the temperature on the boiler tho', should I be changing it ? There's nothing in the meagre manual.

[bhg481]

In theory, when you design a CH system you calculate the size of radiator required in each room by assuming the outside temperature is zero deg and that the boiler temp will be (say) 60deg; you then decide what temperature you want in each room, calculate the heat loss through the walls and windows both to the outside and adjacent rooms. Having done that you can calculate the size of radiator required in each room and fit them. If you increase the boiler temperature all your rooms will be hotter than the design temperature. You then fit a room thermostat in a "neutral" room this will switch-off the boiler when the desired temperature is reached; then all your rooms will be at the desired temperature.
In practice it's simpler to fit TRVs on all radiators bar one so that room temperatures can be easily adjusted.
In your case the thermostat in the hall is controlling the whole house and will switch off the heating when the temperature in there reaches 15deg - turning up the boiler temp will have no effect on that but it will allow the house to heat up more quickly. It could also be that, with too low a boiler temperature, the house will never reach the desired temperature in extremely cold weather.
If the rads are warm at the top they don't need bleeding. If your house isn't as warm as you'd like it to be, turn up the hall thermostat.

[Old_Geezer]

I doubt it. If no water is flowing to the rads then the boiler should know it's hot enough.

I tend to leave the boiler settings alone. Got them right when I first moved in, the BG annual service engineer took over from there.

[The Builder]

Turning a boiler stat down is false economy, CW. Apart from that, as bhg has said, nothing will warm up sufficiently.

Heat temperature at the boiler should be AT LEAST 60 degrees. On a rotary dial, this is usually around three-quarters of the way round.

I'm afraid it's no wonder your rads are warming up ;o)

[The Builder]

^^^^ oops ... no wonder they are NOT warming up ^^^

[CW1]

Thanks guys ... so boiler temp just dictates how *quickly* the rads heat up, ahhh. Will have to tell neighbour to turn his up again, & turn his thermostat down ...

My boiler's still going so guess, even after a couple of hours, air round the thermostat hasn't reached 15°. Have now turned boiler temp up to 60° (though "default" was 30° Old_Geezer, & boiler was serviced in August), guess that's why it's taking so long, hopefully just this 1st time .

Am a little more the wiser so thanks :)

[Palustris]

We have thermostatic valves on each radiator so that they come on when the temp in that particular room falls below the setting on the radiator. So in the unused bedrooms the valves are closed right down. When we moved here the thermostat was in a room which no one used and set the temp for the whole house. Silly really. The valves are easy to fit too.

[KARL]

Everything should revolve about what you are intending to achieve. If a single thermostat is to govern whether the heating is on or not then it must be sited where heat loss is greatest and the temperature slowest to reach the target or quickest to cool down (likely to be the same location) - otherwise the heating will not react promptly to changing conditions. If you are not going to heat the whole house equally (i.e. no heat loss between rooms, only to the outside) then the thermostat alone cannot be expected to satisfactorily control the operation and something like the "Old Geezer technique" must be resorted to. Talking of radiators getting too hot does not make a lot of sense because (with thermostatic valves) they only get hot because they are working to bring the comfort to target - if they can't get hot because the boiler does not deliver heat then the house will remain cold. The positioning of radiators is very important - to be correct they should be below windows or at least very close to them plus one at each external doorway. In the UK there are loads of examples where radiator location is wrong, they are then usually clustered at the entrances to each room (nice and cheap to install but draught inducing, prone to causing damp patches/areas and hopelessly ineffective in modern terms). The UK is relatively new to central heating, inexperienced in design and operation and on top of that operates at far lower heating levels than is found elsewhere because heating has lower priority than in other countries (others regard the UK as a noticeably cold country, including by those whose countries have a colder climate) and thus knowledge is slow to catch on, a vicious circle.

[CW1]

I have trvs, my neighbour doesn't (I have suggested he think about getting some, if only for the lounge), so don't know why his rads got so hot. It was all so much simpler before I moved, with a wireless thermostat, & on mains gas - being on calor now (& just ordered new bottles yesterday), I'm much more aware of how much I'm using.

As for positions of rads, I'm not changing those ! LOL I've 4 in the lounge, but the windows all pretty much go to the floor (French doors, picture windows, side window) so they're more opposite windows rather than under, though 3 are by internal doors. The thermostat's in the hall, opposite the front door, so I've just left internal doors open. Once I'd turned the boiler temp up it did get very warm in here so did turn the thermostat down ! This seems to be the "norm" in these park homes - have heating on for a short time & the heat is just retained, which I'm not used to having moved from a house where I basically had the heating on quite low but all the time.