Cold downstairs radiator

[kevinPaul]

I have a back boiler on the 1st floor of the house (3 storey house). The pipes for the ground floor are in the floor of the 1st floor so these pipes feed the first floor and the ground floor (by dropping down to the ground floor). Recently one radiator is cold on the ground floor (large rad 7' x 2'). There is hot water up to the in valve but the rad is cold. So what have I done? Removed rad and flushed, attached hosepipe to in valve and turned on valve - excellent flow. Done the same on the return valve - excellent flow. A small amount of sediment came out of the radiator and out of the return pipe. Reconnected everything and......no difference. Radiator is fully bled, valves are fully on. All other radiators are hot, including the one on the ground floor immediately prior to the cold radiator downstairs. I can think of nothing else to do. Any ideas?

 

[Jonnie]

have you tried turning all the rads off except the cold one

 

[kevinPaul]

I haven't tried that yet. The radiator has been hot for the last 2 winters without a problem and so I haven't considered rebalancing (I guess that's where you're heading). I'll give it a try, but won't be until tomorrow

 

[kevinPaul]

I turned off all rads except the cold one and the cold one got hot. I guess this means that I need to rebalance the system, but why? The system was working fine until a few weeks ago and then suddenly this one rad went cold - nothing had been changed. Could it be the pump that is losing efficiency - the rad is, I think at the end of the system?

Thanks

 

[seco services]

maybe just an airlock in the pipe.

 

[kevinPaul]

I guess I'll give it a bit of time and see what happens

 

[lkuya]

has it got a trv

if so it could just be that stuck