Living Room Radiator Not Getting Hot

[terryplumb]

How long is quite a while ,weeks, months,years ?
Was any work carried out involving other rads ,BEFORE the problem rad failed to heat ?

 

[WSB]

Been about a year or so.
Did have the cylinder changed prior to that but not sure if that's related.
Have bled all the rads and only water coming out.

 

[terryplumb]

Is the system sealed/ pressurised ,or fed from a loft tank ?
Close one valve on the rad and open the air bleed valve ,let water run out for 1 full minute.
Then open that valve and close the other valve ,and again bleed water out for 1 full minute.
If water doesn't flow freely ,both times ,one valve is blocked , or the pipework to it is.
If system is pressurised ,you will need to keep pressure topped up whilst doing the above.

 

[WSB]

Fed from a loft tank.
Will try what you say tomorrow. Bit tricky though as some valves are jammed.
When i bled the problem rad yesterday i did empty about half a pint. Will try more

 

[terryplumb]

You may well have bled it ,but with both valves open that's not telling us anything. The rad that doesn't heat only has two valves ,which on that rad is jammed ? And how do you know it's not jammed closed ?

 

[WSB]

Sorry was talking about the valves on the other living room rads.
The problem rad left valve appears to work.
Not a cap on the right side but will try with a spanner.

 

[DP]

Could it be that the pump is on its way out. Namely, hasn't got the ooomph to push the hot water to the rads furthest away?

Unlikely as rest of the system is working

 

[DP]

Sorry was talking about the valves on the other living room rads.
The problem rad left valve appears to work.
Not a cap on the right side but will try with a spanner.

Post a picture of jammed valve.
Is the pipe plastic and what diameter

 

[WSB]

All metal pipe and fittings except the actual turning cap itself of course. 15mm soldered copper piping. Have attached photo of one of the jammed valves.

 

[WSB]

Ok folks. Have found that both valves on the cold rad seem to turn without difficulty and as far as I am aware, I am able to switch them fully off and fully on.
As TerryPlumb suggested earlier I switched off one valve, bled around a pint of water out, switched it back on and repeated with just the other valve (other one closed) open emptying another pint of water.
No air came out at all. Have switched the heating back on but as yet the rad is still cold as are both pipes coming to/from it.
After a little further time the right hand side pipe (one without plastic turner) was getting slightly warm.
My guess is that the adjsutable valve (not TRV) is usually fitted to the flow and the return is on the other side which just has a cover?
But then maybe this is the other way round, as I suspect the flow pipe would be getting warm and the return still cold. Not possible to have the other way round.

Could I be right in saying that the right side (without plastic turner) is actually my flow (as that was the only pipe getting warm, albeit slightly) and that the left side with the plastic turner is actually the return?

Anyway, is there anything else I can try? Such as bleeding more than a pint each time or maybe tryy bleeding with both valves closed?
Or am I in the realms of switching off both valves (hoping they close properly) removing and then flushing out the rad?

Must say that the water coming out, although slightly sulphurous, is clear.

 

[terryplumb]

Just to prove that both valves actually close fully internally ,close both and try bleeding . If water ceases to flow from the bleed valve ,then open both valves fully.
Then go to EVERY other rad ,and close one of their valves ( preferably NOT their lockshield ).Run heating and see if cold rad now heats fully.
The flow pipe will heat first by the way.

 

[BlueLoo]

All metal pipe and fittings except the actual turning cap itself of course. 15mm soldered copper piping. Have attached photo of one of the jammed valves.

They look ancient.

I'd be removing the rad and flushing them out.

 

[mcmoby69]

Check pump for blockages or restriction and any pump valves.

 

[WSB]

Ok folks,
Have turned off a few rads and now the cold rad is getting nice and hot.
Will leave it for a bit and then try switching the others back on.
Bit concerned that doing so will make the dodgy rad cold again.
If that is the case, what do you think the problem could be?
Pump not powerful enough (Grunfoss)?
Anyway, fingers crossed for now and I'll keep you updated.

 

[Madrab]

When you start turning on the others, do it via the lockshields. Makes sure they're all closed and then crack them open 1/2 turn each time until you feel the flow pipe start to heat up, then move onto the next until you can just get heat flowing through them all.