I've just had a condensing Worcester 24i junior installed.
If I control the room temperature using the TRVs (as advised) what should I set the temperature control on the boiler to be?
I've got a digital timer on it, I've got a small radiator near the boiler without a TRV but I've not got a room temperature control.
Most efficient boiler operation is to have the water as cool as you can whilst it is still able to heat the house. You will need to turn the water temperature up higher as the outdoor temperature drops, and also if you are heating up the house from cold. Exactly what that temperature is depends how large your radiators are. If they were designed for a condensing boiler, it might be as low as
45C (which is what I use), but if they predate the condensing boiler, you might need the water hotter in order for the radiators to get enough heat transferred into the rooms. Try turning it down until the house starts getting colder, and then turn it up a little.Sounds like the installation does not conform to Part L. There should be something to stop the boiler firing up when there is no demand for heat, and that's usually done with a room stat in one room which doesn't have TRV's fitted. Does the radiator with no TRV stay hot all the time?
Thanks for the good advice.
I'm in Scotland and this combi is a replacement for a non-condensing Ariston unit which failed after 10 years.
The radiator without the TRV does stay warm - very warm, easily the hottest one in the house (it's in the hall).
I was concerned that if I had the heating on the boiler set to max then the TRV would reject the hot water and the radiator without the TRV would get all hot water and get dangerously hot. I guess that having a room stat would avoid this?
In that case, Part L may not apply (I don't know the Scotish equivalent).
It would avoid wasting energy when the hall doesn't need any more heat. Ideally, you would have it in the room which is slowest to heat up, so it doesn't switch off until the others are up to temp, but it must go in the room with no TRV, the hall in your case.
Interesting - I'll look into buying one.
Turning down the thermostat that low, while aiding boiler efficiency in space heating applications, is not really compatible with heating a hot water cylinder to usable, i.e circa 60 deg C temperatures.
It's a combi boiler. It fixes the hot water at 55C regardless of radiator temperature.
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