cold radiator

[ukheather]

We have a cold radiator in the living room that is cold at the bottom and only lukewarm at the top. We have just got a powerflush and it isn't any better. He checked the thermostats and they are fine.

All the other radiators are very hot.

The plumber said that there is probably a kink in the pipe that is stopping the flow of hot water. The radiator on the room above is wamer but still not hot.

He said he could replace a section of pipe from the living room to the other radiator to make it a thicker pipe instead of 8mm microbore.

Should I get this done, or is it silly only replacing a small run of piping? Should I get the whole central heating pipework replaced?

Is there anything else it could be?

 

[John506]

Should you get the whole central heating system pipework replaced?.. NO! (That's a rash and expensive decision)

Where is the boiler and were is the cold rad, maybe your system isnt balanced out?

 

[MANDATE]

I think I'd be checking if you have a by pass valve that connects flow to return. water will take the easiest route and the by pass will have less resistance than the radiator.
I'd also consider the pump, that could have partial blockage which would restrict the flow.
I had similar type problem on a radiator that was furthest away from the boiler. It was only when pump stopped and was removed for its replacement that the inlet and outlet holes were found to be almost blocked. The 20mm holes were down to about 6mm.

 

[ukheather]

The cold rad is the furthest away from the boiler. I asked him if it could be a balancing problem, but he said no.

 

[John506]

Maybe the powerflush didn't do a very good job? Take the rad off yourself and flush it out with a hosepipe in the garden or something.

 

[spacethegas]

it sounds like that may well be the problem.

if you can afford to repipe the system i would recommend it.

 

[ukheather]

Maybe the powerflush didn't do a very good job? Take the rad off yourself and flush it out with a hosepipe in the garden or something.

He took it off after the powerflush and hosed it out to make sure it was ok

 

[John506]

He took it off after the powerflush and hosed it out to make sure it was ok

Fair enough