Radiators - Hot at the top, cold at the bottom

[kieransampson]

Hi

Something of a dilemma here. We've got a BGas agreement and have mentioned this a couple of times to them, each time we've been told we need to have a device fitted near to the boiler to extract any sludge in the system. We've also been told that the boiler is at its limit for the size of the house. It's an ICOS, but not sure on the model - either HE15, HE18 or HE24.

Our house is a 3 storey town house. 3 rads on the top floor, one of which is a large towel rack. On the middle floor we've got 4 rads, one of which is a large towel rack. On the ground floor we've got 6 rads.

All the radiators have thermostatic valves. The house is 5 years old.

On the top floor, even when the valve is set to 0, the radiators still get hot.

On the ground, the radiator in the lounge is often the coldest and when it is warm, the top is hotter than the bottom. The second radiator in the lounge is often hot.

The towel radiator on the 1st floor is often cold, as is the bedroom radiator
on the 1st floor.

Really just after some advice here:
1) given the house is 5 years old, is it likely to have sludge in it.
2) is the boiler suitable
3) does the system need re-balancing

Many thanks

 

[dcawkwell]

Something of a dilemma here. We've got a BGas agreement
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Give them the push they are hopeless
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and have mentioned this a couple of times to them, each time we've been told we need to have a device fitted near to the boiler to extract any sludge in the system.
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Possible but most likely they are trying to sell an expensive powerflush at £600 a go.
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We've also been told that the boiler is at its limit for the size of the house. It's an ICOS, but not sure on the model - either HE15, HE18 or HE24.
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Unlikely. Number of radiators * 1.5 give the size of boiler you need roughly. So 10 radiators = 15kW boiler.
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Our house is a 3 storey town house. 3 rads on the top floor, one of which is a large towel rack. On the middle floor we've got 4 rads, one of which is a large towel rack. On the ground floor we've got 6 rads.
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So you have 13 rads therefore 19kW boiler needed
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All the radiators have thermostatic valves. The house is 5 years old.
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Plenty of insulation therefore very little heat needed
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On the top floor, even when the valve is set to 0, the radiators still get hot.
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The thermostatic valves need replacing
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On the ground, the radiator in the lounge is often the coldest and when it is warm, the top is hotter than the bottom. The second radiator in the lounge is often hot.
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System needs balancing. My guess is your boiler is upstairs rather than on the ground floor.
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The towel radiator on the 1st floor is often cold, as is the bedroom radiator
on the 1st floor.
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System needs balancing
------------------

Really just after some advice here:
1) given the house is 5 years old, is it likely to have sludge in it.
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Possible but very unlikely if it is a sealed system (no central heating header tanks.
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2) is the boiler suitable
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see above sizing wise
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3) does the system need re-balancing
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Yes. Yes. 20 minute job see the online help about how to do this.
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(Give BG the push)

 

[45yearsagasman]

You make it all sound so simple.

 

[xr4x4]

It is..!

 

[kieransampson]

Many thanks for the useful and informative response.

To add to my points, the boiler is on the ground floor. I believe it's a condensing boiler. Our water tank is on the top floor.

So, if we need a 19kw boiler, then I need to check to make sure we've got an Icos 24.

I'll have a look at the re-balancing article and will prob get in touch with Bgas again.

Many thanks.

 

[kieransampson]

Not sure if this will help.

I gave the valves a whack with a mallet yesterday and this morning they were all nice and hot. Possibly sludge or a sticky value that is playing havoc with the balancing of the flow in the radiators?