Radiators warm at top, cold at bottom

havabrew · 7 Sep 2006

We've had a new boiler fitted, all works fine except three downstairs radiators. One remains cold at all times, the other two will warm up only when all other radiators in the house are turned off and then only the top will warm whilst the bottom remains cold.

The system has been bled repeatedly.

I am unsure if these radiators worked prior to the new boiler being fitted.

Any ideas please?

JohnD · 7 Sep 2006

Was the system powerflushed? Or have you given it a clean?

Do you know how to balance the radiators?

havabrew · 7 Sep 2006

I dont think the system was flushed, but the plumber has been back since and balanced the rads. This didn't work so Ive been turning radiators on and off left right and centre.

The two rads that do get warm are no where near as hot as the radiators in the rest of the house...

kevplumb · 7 Sep 2006

turn the ones that are working off it may be trapped air the pump might clear it

JohnD · 7 Sep 2006

If they don't get hot when the others are turned off, then either you have a design fault, or they are clogged with corrosion.

Does your system have a Feed & Expenasion tank in the loft? If so, have a look up there and see if it has fine mud at the bottom (brown or black).

Do you know how to take a radiator off and empty it out?

Can you afford a couple of hundred to have your plumber fit a Magnaclean and drain valves?

havabrew · 7 Sep 2006

Thanks for the replies, I have turned the heating on with only one rad open, and have done this in turn with all three - they just get warm.

After paying for the boiler I cant even afford the gas to run it.

Looks like Im taking the radiators off one by one and cleaning, very difficult to do whilst crossing my fingers!

Cheers

JohnD · 7 Sep 2006

OK. After taking them all outside and hosing them through (tap them with a mallet to loosen deposits as you do this) buy a litre of Chemical Cleaner, and a litre of Corrosion inhibitor. Sentinel and Fernox are two good brands. Drain and rinse well between treatments.

Have you got plenty of drain valves? If not, or if you have a solid ground floor, you can get rad valves with drain-offs incorporated, which I find very handy.

It is quite important to get the old rubbish out when you have a new boiler, or the old stuff will collect in it.

havabrew · 7 Sep 2006

Thats my weekend taken care of. Many thanks

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Radiators warm at top, cold at bottom

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