UFH house seems cold

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6 Jul 2012
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Berkshire
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Hi - we have a gas boiler (about 2 years old - Worcester Greenstar). The house is 2 years old.

It runs the hot water and water-UFH throughout the house.

As the weather’s become colder I’ve noticed that the thermostats in the rooms struggle to ever reach 20 degrees even though the UFH is calling for heat (and the boiler is responding) for 18 hours a day. Normally the rooms are at 17-18 degrees. It a new-build house so well insulated.

The floors are warmish to the touch mostly but I wonder if there’s a problem.

I checked the boiler (see pic) and pressure gauge is at zero. In a previous house with a sealed system and normal rads, I knew to keep the pressure above 1 bar otherwise the boiler would cut out, but is the same true with UFH? Should the pressure be higher and would it make any difference (it hasn’t cut out at zero bar).

Also, the central heating temp control on the boiler could be set higher but again, would this make any difference (sorry if that’s a silly question)?

Many thanks

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Top the pressure up and post some decent, focused, pictures of the ufh manifolds, with close ups of the flow guages and blending valve.

(some members don't understand what a focused picture is ;))
 
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I’m guessing it’s not coincidence that the gauges are rising having topped up the boiler?

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Standard size expansion vessel inside the boiler?

No extra expansion vessel anywhere?
 
I’m sorry I don’t know what an expansion valve is :) How can I tell if there’s another one somewhere? I’m guessing the only other place could be upstairs in the airing cupboard? See pic...

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Nope, that's for the unvented cylinder. The one you're looking for is usually red.
 
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Yeah OK I just googled it, I know what you mean now. There is no expansion vessel anywhere else.
 
Out of interest (and congratulations on decent pictures too (y)) can you show us the silver data plate on the side of the cylinder?


What setting is the blending valve on the manifold? It is the dual under the pump on the left.

Yes, those two pressure guages should roughly match each other and be between one and two.
 
Yeah OK I just googled it, I know what you mean now. There is no expansion vessel anywhere else.

It will be in the boiler then, and maybe too small.

If the pressures rise quite high when the heating is running for.a while, the safety valve may be opening and dumping the pressure outside. This will require an, additional vessel fitting the one in the boiler checking and a new safety valve.
 
Typical boiler slinger install then, get it in, get paid and then get the fook out of here! Getting the original installer back might prove difficult........
 
Hi Dan, which silver data plate do you mean? On the hot water cylinder? - I can’t see a data plate.

I see what you mean about loop 9 being low on the original pic but it seems to have filled up since topping up the boiler.

Forgive me, I don’t know what the blending valve is, do these pics help?

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