Cold Radiator in living room

mmcmahon

Hi

I'm having a problem with a radiator in my living room not heating up properly. It's a double rad and was added maybe 6 months ago replacing an older single one, it never heated up properly but until recently I never really needed it on.

It's warm at the top and cold at the bottom. The pipe feeding the rad is boiling and the other pipe cool / tepid.

I tried turning off all other radiators in the house and leaving this one on and it got warmer but was still cool at the bottom. I read I may need to balance the system but I would have thought that if I turned off all other radiator this one should be hot all over. Is this the case? Or could opening the locksheild valves on other help? (I have tried this on a few but it made no difference)

Could the pipe work be the problem? (8mm microbore)

Someone also suggested sludge could be present in new rad. Is this likely given that it is new? I opened the lockshield valve and clear water poured out so I'm assuming there is no sludge, is this correct?

Any ideas?

Thanks

silvercar

I had this problem. Sludge sits at the bottom of the radiator.

I turned all the other rads off and left this one on until it got really hot.

you may have to do this more than once.

The other possibility is an air block in the pipe somewhere. when the heating is cool and off try bleeding all the radiators.

woo

I would try the bleeding first - that has been an issue on a few of our radiators.

Canucklehead

Hi.

If both valves are open on the offending rad and all the others are off you should have heat . I assume you have a pipe at each end of the rad?
If you have a suspended floor( ie.floorboards and a space underneath) then it is possible that when the new rad was fitted the pipe under the floor has been kinked. 8mm pipe is easy to crush.
Corgi Guy.

Mr_Grumpy_7

It could be one of 2 things. Firstly, turn all the other radiators off and if possible turn the pump to high. This will help clear an air lock if that is what the problem is. You may need to bleed the radiator when done.

Another cause maybe a build up of calcified sludge in the microbore pipe to this radiator. I had this problem a few years ago which only affected the one radiator. When I drained the system and removed the radiator valves I found that the feed pipe was blocked by black calcified flakes. These were located where the valves attaches to the pipe and were easily cleaned out. I then hosed out the radiator, put it all back together, and refilled the system, adding some Sentinel X400. After a few weeks I drained the system, and re-filled it adding some X100 inhibitor.

mmcmahon

I am assuming that the feed pipe is the one that heats up quickest. Is that correct?

I have one really hot pipe and one cool one.

Mr_Grumpy_7

mmcmahon wrote:

I am assuming that the feed pipe is the one that heats up quickest. Is that correct?

I have one really hot pipe and one cool one.

The feed will be the hot one, the return should be slightly cooler but not cold, which would suggest there is a restriction in the circuit, most likely on the feed side. This assumes both valves are fully open.

Lord_Gardener

We always find this problem is air lock or a jammed valve! Bleed and open/close valves several times should cure problem!