Really dim question about boiler settings

tinselworm

Hi all

New here with what's probably a really dim question, so apologies in advance.

I've been reading the threads about reducing gas bills with interest, as I've regularly been clobbered with large bills and I've come to the conclusion it's because I just don't understand my heating or how it works. Never have, really; I've just switched it on when I get cold and off again when I've warmed up. So I've set about trying to find out and one of the things I've discovered is that knocking down the temperature by say 1 degree can significantly reduce the bills.

My very simple question is: How can I tell what temperature my boiler is heating the flat to?

My rented flat has a Worcester 24CDI boiler in the kitchen. There is no specific temperature indicator, just a dial with four settings on the front, 1-4, which I can use to set how warm the flat gets when the heating is running. But it doesn't give me any indication of the actual temperature, just this abstract one that doesn't really mean very much. So if someone says to me 'Turn your heating down to 18 degrees' - how do I know what setting to put it on to achieve that?

There is no thermostat in any of the rooms so I can't tell by using that either, because, well, there isn't one. The only radiator that has any kind of dial on it is the one in the bathroom, which I've set down very low as I'm hardly ever in there.

So, if I have my boiler set to say 2 out of the 4, how warm is it getting in terms of degrees? Is there any way to find out? (the manual doesn't tell me) Or is it not that simple?

macman

The temp control on the boiler only controls the temp of the water exiting the boiler to the CH circuit. It doesn't control actual room temps. Turning it up will heat the flat faster, but not control the temp.
If you want to know how warm a room is, just use an ordinary thermometer.
The system is outdated and really needs fitting with TRV's and a room stat.
Typically in winter you could be setting it to around 2/3rds of the maximum.
I suggest that you download the user manual from the WB site to learn more about the operation of your boiler.

tinselworm

Hi macman, thanks for the reply.

I have read the manual, but it doesn't give any indication of what the 1-4 settings actually mean in terms of the temperature of the water that leaves the boiler and the resulting bills. The rooms are hotter when it's on a higher setting (and actually I don't have it higher than 3 usually because I don't like it too hot), but that's all I know.

I don't know how to fit a thermostat, and in any case the flat is rented and I probably won't here much longer.

Presumably though, if the 1-4 dial is set higher to heat the water that goes into the radiators to a higher temperature, that makes the rooms hotter and it will cost me more? I tend to have it set at around 2, but sometimes that gets really flippin' cold. If it's on 2, what sort of temperature is the water leaving the boiler? This is what I'm not understanding; the manual doesn't tell me that and I can't find an answer anywhere.

Every rented flat i've lived in that's had GCH has had this kind of system in it - no dials or buttons on the walls or controllable valves. So I've always had to do all the temperature control from the boiler and then I'm just guessing as to how much it's costing me. Depressing.

macman

The temp of the water in the circuit does not correlate to any precise room temp.
I it's higher, the flat will heat quicker. it will only cost more if it's unregulated by TRV's or a room s'tat. Talk to your landlord about a simple room 'stat fitment and TRV's. Every new system must have these.

Yolina

I'm nor sure how helpful this is going to be but for my 20+ year old Potterton boiler, the range is 1 to 6 where, according to the manual, 1 is around 55c and 6 is around 82c. I've always had mine on 2 (so around 60c for my boiler) and control room temp with TRVs (no room thermostat) but I know you haven't got TRVs. It should be easy for your landlord to fit a room stat or TRVs so ask!
*If* the range on more recent boilers is also 55c to 82c then it's easy for you to work out what 2 and 3 are

tinselworm

That would seem to not be the case with this one, macman, not that i'm trying to disagree, just writing down my experience of living with it. If I set the dial to 2, it never ever gets as hot as it does if I have it on 4, even if i leave it on all day, so it doesn't seem to be a case of the room heating up quicker, it just never gets as hot at all. Re the landlord, I'm going to be moving out before next winter so there's not much point badgering him to upgrade the system - i'll leave that for the next tenant if they're unahappy with it, but thanks for the suggestion.

Yolina, thanks, that's really helpful, just the kind of info I was after.

Yolina

The only thing is that, as I've said, I don't know if more recent boilers have the same kind of temperature range as the "vintage" ones

tinselworm

Good point! I have no idea of the age of this boiler, sadly, only that they were discontinued in 2007.

I think on reflection I've worded my question a bit poorly, so I'll try again.

I know that you can't heat the rooms themselves to a specific temperature without a thermostat, but since I don't have that kind of system, I have to work with the system I actually do have (like I say, the flat does not belong to me), so that's what I'm trying to do.

I guess the question is, given that I don't have all these extra bits: what is the cheapest and most efficient way to run the system I actually do have? (boiler + radiators, that's pretty much it)

If, for example, knocking the CH temperature dial down from 3 to 2 corresponds to a few degrees less on the water coming out of the boiler (random figures plucked out of my hat, because I don't know them: say 3 heats it to 70 and 2 heats it to 60), surely it'll take less gas, and therefore cost less, to heat that water to a lesser temperature to begin with? Is there any way I can find out what the water temperature difference is between the settings if it doesn't say in the manual? And can I convert that to a saving? (for example, what I'm after is something like 'if you have the control set to 3 instead of 2, it'll take an extra [x-number] of units per week to run it' - from there I can do the maths and work out how much that is in ££). Appreciate that this would depend on someone knowing the inner workings of this particular boiler, but perhaps someone else on the forum has one.

macman

It takes a fixed amount of energy, i.e. gas, to raise the temp of your flat from temp A to temp B. Whether you do this slowly (with the setting lower) or faster (with the setting higher) makes no difference whatsoever to the gas bill.
The two (boiler output temp and room temp) cannot be correlated 'universally,' because the rate of heat loss is different for each property. So if you set it on 2, your property is losing heat almost as fast as the system inputs it-though obviously this is dependent on the ambient temp. Which is why I suggested a higher setting in winter.

tinselworm

macman wrote: »

It takes a fixed amount of energy, i.e. gas, to raise the temp of your flat from temp A to temp B. Whether you do this slowly (with the setting lower) or faster (with the setting higher) makes no difference whatsoever to the gas bill.

Ahhhh, I see. I'd never thought about it like that before, that makes perfect sense - thank you (I've only ever had gas during the last 3 or 4 years, so I don't really understand how it works) I guess I thought the higher the setting, the hotter it would run and the more expensive it would be.

I'd imagine the rate of heat loss is shocking in this flat, to be honest; the entire fourth wall of my living room for example is made up of draughty old sash windows and a single-glazed garden door, and there are six almost floor to ceiling sash windows in the bedroom. And high ceilings. I would imagine that the heat escapes almost as fast as it arrives. When the heating goes off after the timer switches off, it's freezing cold again within half an hour; it's almost not worth having it on at all.

Although that said, npower have just told me my average usage is about 3 units of gas a day, so I'm not quite seeing why the bills are so mad.

macman

Metric units or imperial units? It's marked on your meter.