Please help with a cold radiator

[NinReznor]

hello, i was wondering if some expert could help me. i have a radiator in the upstairs bedroom its a drayton radiator with a thermostatic value, and its been stone cold for months. it wasn't a problem in the summer but now its winter my son is complaining about the cold.
i read some threads on here about trv pins being stuck so i tried the advice and took of the cap and tapped it with a small hammer it didn't budge but i was able to pull the pin up about 3-4mm with some pliers. after i did i noticed the pipe on the right hand side was getting hot (the pipe with the thermostat), where as before it was stone cold.
although the pipe is hot the radiator will still not heat up and i don't know what to do next or how to make it work.

any help would be greatly appreciated.
thank you

 

[sloppytom]

try turning other rads of and then try to release pin again. Trv valves rely on the water to keep the washer moist and stop it sticking to its seating, with the other rads turned of your will get more pressure from the pump behind the valve to fully free it.

 

[D_Hailsham]

i tried the advice and took of the cap and tapped it with a small hammer it didn't budge but i was able to pull the pin up about 3-4mm with some pliers. after i did i noticed the pipe on the right hand side was getting hot (the pipe with the thermostat), where as before it was stone cold.

Just wondering what you expected to budge. What did you tap - the valve top or the body of the valve? Hopefully you meant the body of the valve!

Are you saying that the pipe connected to the TRV did not get hot until you tapped the valve?

If you press down on the pin and let go, does the pin spring back up again?

Does the pipe at the other end of the radiator get hot? If so, is it hotter or cooler than the pipe to the TRV?

Is the radiator stone cold or just lukewarm?

 

[NinReznor]

i took the cap off and tapped the side of the valve but the pin didn't release.

the trv pipe didn't get hot until i pulled the pin out a few mm.

No it doesn't spring back up and the pipe at the other end is cold aswell same as the rad, the rad is stone cold.

after turning off all the other radiators though the rad has got a tiny bit warmer. i will wait an hour or so and see if the rad heats up before i try anything else. although i dont belive the pin has released.

EDIT: the rad is getting a lot warmer now, altough if i turn all the
other radiators back on would that not bring down the pressure and just make the radiator cold again?

Thank for all your help.

 

[sloppytom]

hopefully the washer should now be fully free and operate normally. another thing to try is to balance system better, by turn the lockshield valve side of rads down a touch on the rads that get hot quickest.

 

[bengasman]

Some draytons seem to be sensitive to dirt and corrosion, best to replace them as they are not expensive.
Invariably, when this happens the system needs cleaning.

 

[NinReznor]

hello again, I kept all other radiators off for a while, so i could see if the faulty one would heat up properly and it did. the problem i have now is that when i turn the other radiators back on the faulty rad goes cold again. any ideas on what's causing it?

Also where is the lockshield valve?

Sorry about all the questions.

EDIT: If it helps my boiler is a Valliant VP5-ZE

 

[D_Hailsham]

hello again, I kept all other radiators off for a while, so i could see if the faulty one would heat up properly and it did. the problem i have now is that when i turn the other radiators back on the faulty rad goes cold again. any ideas on what's causing it?

Almost definitely a balancing problem. What speed is the pump set to?

Also where is the lockshield valve?

Each radiator should a valve at each end. One is adjustable - either a wheel valve or a TRV; the other valve is the lockshield valve. It usually has a cylindrical plastic cap, which is either a push-fit or held on by a screw. When you remove the cap you will see the shaft of the valve which can be turned using a small spanner, pair of pliers etc. The lockshield valve is used to adjust the flow through the radiator to get the correct temperature drop between the flow and return pipes.

my boiler is a Valliant VP5-ZE

That's not a Vaillant boiler model! Do you have the User manual - if so, what does say the model is? Failing that, there is a data panel on the boiler which should have the info, including the GC number.