1 Cold radiator downstairs. pipe hot up to about 12 inches away from valve inlet

[J All]

What could be wrong and what can I do about it? Water and heating on gets hot water hot and all radiators hot except 1 downstairs which remains cold. The downward pipe gets hot but there is a cold area in the pipe about 12 inches before it travels to the radiator valve which is open. Working last year. I have tried bleeding. No air comes out.

 

[JohnD]

Turn all the hot ones off. What happens to the cold one?

was it added after the rest of the system had been designed and installed?

 

[J All]

AS fa as I know the radiators were all installed at the same time. We have been here 20 years and it has worked fine. I will try and do what you suggest tomorrow and let you know. I have read that the system may need balancing by doing what you suggest then gradually turning them on one at a time.

 

[SammyInnit]

I have read that the system may need balancing by doing what you suggest then gradually turning them on one at a time.

If it was working fine at one point it suggests now that there's a fault.

Is the TRV seized? While you might have it at the 'fully open' position, the TRV valve pin could have seized if it's spent a long time closed. Presumable the lock shield is fully open.

If it is the TRV you need to remove the head and give the centre pin a light tap with a hammer repeatedly until the pin springs up.

Closing down all other rads will send to that one rad only and that will give an indication if there is a problem with that radiator alone or if it's on the boiler but considering all others are hot it's unlikely.

 

[nigelknows]

Could be stuck valve or crud in rad obstructing flow .

 

[J All]

I do not have TRV's. I tried turning all rads off except the problem rad but 2 of the rads won't turn off and the pipe is now cold leading to the affected radiator. I opened up the lockshield vave. Should I keep it open. Not sure what it does? balances?

 

[lostinthelight]

When you bled water could have been coming to rad from either pipe, Try closing the rad valve opposite end to the one that has the cold pipe running to it and see if anything comes out of the bleed nipple then.

 

[SammyInnit]

I do not have TRV's. I tried turning all rads off except the problem rad but 2 of the rads won't turn off and the pipe is now cold leading to the affected radiator. I opened up the lockshield vave. Should I keep it open. Not sure what it does? balances?

Is there any chance parts of your system is fed end to end? If there are no TRVs and only lock shields and closing some has stopped any hot flow at all it's possible.

If you open up one of the two you closed, does the other get hot again along with others?

Have you ever had the system power flushed?

 

[lostinthelight]

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