Electric heater in one room vs centrally heated whole house

spinningsheep

Sorry to sorta hi-jack this thread, but I am a wee bit confused as to how a central heating system works with the different posts I have seen on the subject. I have a 20yr old + Glowworm FuelSaverF non combi boiler which runs 9 non TRV radiators and a towel rail. One radiator in non used bedroom is off (valve stuck anyway) . My understanding was, my old gold coloured Honeywell thermostat in my hallway is set to say 18 degrees, when the temp in that room hits 18, the thermostat clicks off and so the boiler stops firing, when the temp falls below this again, the boiler fires again, so and so forth. It is also timed to come on and off at the times I request. The hot water can be used independant of the central heating, although I do not use it like that, the hot water is heated in the tank when the heating is on, I do not use the hot water in winter. When my heating is on timed for a couple of hours in the morning, the towel rail stays cold. Yet when I have it on in the evening for 5 hours, it gets nice and warm, yet still not HOT. When the temps outside were -10 or so recently and I left the heating on constantly but on about 15 degrees, the towel rail heated up nicely. Could it be that the boiler is underpowered for the system? I am guessing the system has been added to over time, ie more rads, the towel rail etc, but the boiler has been in situ for 20 yrs or more? Where does the return temp of the water come into it? I am confusaled!!!

joolsybools

Isn't it better to just change to a more modern efficient boiler (assuming you can afford/get credit for this)

spinningsheep

I would love to but it is a rented house and not something I can force

Slinky

On our old system before we extended the house and a lot of it was re-plumbed, I believe the bathroom radiator was heated on a separate plumbing circuit via the hot water tank. I remember the first summer we were here the bathroom radiator being hot in the summer when the rest of the heating system was off. We turned it off in the summer, then back on in the winter and it never really heated up properly again - probably gunge in it's circulation system somewhere. I can see the logic for this of allowing heat in the bathroom when heating the rest of the house is not required.

Could this be the answer for you spinningsheep?

spinningsheep

Thanks Slinky I never thought of that! Will try when I get home, will put the heating OFF and the hot water on for an hour or 2 and see if it heats up. If not, and it is run on the central heating circuit, why does my system behave the way it does?

Cardew

spinningsheep wrote: »

Sorry to sorta hi-jack this thread, but I am a wee bit confused as to how a central heating system works with the different posts I have seen on the subject. I have a 20yr old + Glowworm FuelSaverF non combi boiler which runs 9 non TRV radiators and a towel rail. One radiator in non used bedroom is off (valve stuck anyway) . My understanding was, my old gold coloured Honeywell thermostat in my hallway is set to say 18 degrees, when the temp in that room hits 18, the thermostat clicks off and so the boiler stops firing, when the temp falls below this again, the boiler fires again, so and so forth. It is also timed to come on and off at the times I request. The hot water can be used independant of the central heating, although I do not use it like that, the hot water is heated in the tank when the heating is on, I do not use the hot water in winter. When my heating is on timed for a couple of hours in the morning, the towel rail stays cold. Yet when I have it on in the evening for 5 hours, it gets nice and warm, yet still not HOT. When the temps outside were -10 or so recently and I left the heating on constantly but on about 15 degrees, the towel rail heated up nicely. Could it be that the boiler is underpowered for the system? I am guessing the system has been added to over time, ie more rads, the towel rail etc, but the boiler has been in situ for 20 yrs or more? Where does the return temp of the water come into it? I am confusaled!!!

The return temperature of the water is more a factor with modern condensing boilers; and yours at 20 years old will not be a condensing boiler.

Your understanding of the thermostat operation in the hall is correct and it will turn off the pump.

However the boiler is not firing all the time when the thermostat is demanding heat as the water temperature in the radiators and pipes is set(normally) by a control on the boiler(usually 1 to 6) and when the set temperature is reached, the boiler shuts off.

If you have no TRVs on any radiators or towel rail, then the latter not getting warm is probably because the system is not correctly balanced or, as you indicate, the boiler is having difficulty coping with the system; the heat being dissipated before it reaches the towel rail

spinningsheep

cheers. I put my hot water on for an hour instead of the heating but the rail stayed cold. So it's defintely on the main central heating circuit. Yes my boiler does have a knob for the water temp, but my water tank has a thermostat on it too, which I think is set to about 60 degrees. Should I be running the boiler one on mid or high? If the radiators heat up quicker would this save gas? Or would the extra gas being used for the water to get to temp mean it would cost me more?

victor2

Cardew wrote: »

Your understanding of the thermostat operation in the hall is correct and it will turn off the pump.

However the boiler is not firing all the time when the thermostat is demanding heat as the water temperature in the radiators and pipes is set(normally) by a control on the boiler(usually 1 to 6) and when the set temperature is reached, the boiler shuts off.

This is important to appreciate. The boiler fires to maintain the water temperature, so when the thermostat turns the pump off, the boiler has very little to do.
If you look at your gas meter when the boiler is actually firing, the consumption is quite high, but once the water is up to temp, the boiler shuts off although the heating pump may still be running. You need to look at the gas consumption over a period of time, such as several days, to get an idea of the cost of running the heating.

ixwood

spinningsheep wrote: »

..
Should I be running the boiler one on mid or high? If the radiators heat up quicker would this save gas? Or would the extra gas being used for the water to get to temp mean it would cost me more?

I'd put it on high. As long as you have a thermostat set, the cost won't be any different (as the same amount of energy is needed to heat the room to the required temperature), but it will heat up quicker from cold.

spinningsheep

Cheers ixwood have notched it up to full. Boiler starts to hiss and wheeze though is this normal??LOL