New Condensing Boiler - Lower Central Heating Temperature

oakenlivery · 8 Nov 2009

Last year our 20 year old gravity fed boiler gave up so I took the opportunity to replace it with a shiny new Worcester Bosch 27cdi Combi Boiler which, our plumber advised, would be a suitable replacement.
Everything works fine although we cannot seem to get the room temperatures much higher than 22 degrees Centigrade (which is a lot lower than the old boiler achieved). We now have TVR valves in nearly every room. I have most of them set at their mid position. The main thermostat, a Drayton RF wireless type. is in the entrance hall. This I have set at 26 degrees C, however it rarely gets above 20 degrees. We live in a 3 Bed 1910 end terrace and I have recentl installed double glazing in every room. The loft is insulated and in keeping with the general period of the house we have retained a few open fireplaces which are still serviceable. The plumber also fitted a Magnaclean unit. Could the main thermostat be faulty? Do I need new radiators? Any suggestions would be useful.

jackthom · 8 Nov 2009

Wow you do like it warm but that's OK if you can afford the gas.

I'd say if the TRVs are set to mid range they will be going OFF long before the room temperature gets to the level you require. They probably need to be turned fully on for that Mediterranean climate.

kevindgas · 8 Nov 2009

why not call the installer and ask him?
the first question i would ask is did you range rate the boiler when you installed it? a 27KW boiler is more than capable of heating the house described.
have you got a thermometer? even a basic one that you can place on top of the room stat ? does it read the same temperature or very close?

bengasman · 8 Nov 2009

Go around the rads, and feel for cold spots along the bottom.
What temperature is the boiler set for?

oakenlivery · 8 Nov 2009

Early last year, when we had the cold spell, I turned the temperature setting on the boiler to maximum, it had been set to the 4 mark. This effectively allowed us to stand still i.e. the temperature remained at or about 20 degrees C. As we are now not yet in a cold period, I have returned it to the previous setting.

I did question this lack of heat with the plumber. He believed that 20 degrees was adequate. -- Perhaps you are correct, I do enjoy a warmer environment than most but I do have a rheumatic condition which doesn't like the cold very much.

The installers basic response was see how it goes, if still dissatisfied it may mean new pipes and radiators. After just shelling out £1500 I felt somewhat intimidated!

gigz · 8 Nov 2009

You need to set the CH temp on the boiler to max and have full control at the room stat, if not the boiler stat will be satisfied first.

jackthom · 8 Nov 2009

oakenlivery said:
We now have TVR valves in nearly every room. I have most of them set at their mid position.

Are you sure they are turned up high enough? They should not be closing down before the room gets to the required temperature.

Do the radiators remain hot right to the bottom?

picasso · 8 Nov 2009

an open chimney will suck the heat out of your rooms faster than a boiler could replace it, get a couple of chimney balloons to seal them if your relying on the central to keep you warm.

http://www.chimney-balloon.co.uk/

Gasman77 · 8 Nov 2009

TRV's set to the mid position will start to shut down around 20-22 deg. thats their job! wind them open to max, see if they give you the room temp you want.

If your still not there, and your rads are hot to the touch , either your rads are undersized or your insulation is no good!

Save yourself a fortune and put a jumper on

oakenlivery · 8 Nov 2009

The radiators are all ok with no cold spots. I bleed them regularly and ensure that the boiler pressure is maintained at 1.5bar pressure.

Regarding the Room Stat, I have done what you suggest. The heat in the room did go up slightly, but still a few degrees below maximum I had set on the main thermostat.

Interesting reply from gigz regarding- maxing out the boiler stat. I have been advised to do this before by a colleague but cast doubt on it. My logic tells me, why have a boiler thermostat if it has to be set to max all the time?

landyandy · 8 Nov 2009

It should be set to max if you have a room stat.

Btw does your hot water get hot enough

Andy.

gigz · 8 Nov 2009

oakenlivery said:
Interesting reply from gigz regarding- maxing out the boiler stat. I have been advised to do this before by a colleague but cast doubt on it. My logic tells me, why have a boiler thermostat if it has to be set to max all the time?

The boiler stat is there in case you dont have a room stat.

rojaca · 8 Nov 2009

you've got three responses telling you to turn up your thermostatic rad valves. Your boiler could be pushing water around at 82 degrees but if these are turned down of course the rooms aren't going to get hot.
If your not happy with how your controls all work together then speak to your installer. It is part of the commissioning process to explain these.

oakenlivery · 8 Nov 2009

Yes my hot water is perfectly o.k.

Regading the Boiler Stat. The scales are falling from my eyes!
I can see that this feature would become redundant if room stats are fitted, but are'nt room stats mandatory anyway, or at least in bedrooms?
Why didn't the plumber set it to maximum in the first place I wonder?

Gasman77 · 8 Nov 2009

Why aren't you following the advice people are giving you? turn your TRV's up!!!

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New Condensing Boiler - Lower Central Heating Temperature

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