One radiator not getting hot

[Hepperz]

Hi All

We have 1 radiator that isn't getting hot, and I'm running out of ideas as to why!

Here's the situation and what I've tried so far...

We have TRV's on all of the rads with the exception of the one in the hallway downstairs, which presumably is so that the boiler/pump can still push water round if all the TRV's are off.

All the lockshields are open to varying degrees, and no TRV pin is stuck.

I've tried to balance the system, but it's difficult to do this properly as I don't know how the rads are plumbed in (the house was built in 2001, so I'm presuming a 2 pipe system). So I've been closing the lockshields on the rads that are getting really hot. However, it seems on some rads that what I thought was the return pipe (with the lockshield on) is hotter than the flow?! Our TRV's are Myson 2 way, so maybe they are on the return on some of the rads?

Despite this balancing, and some of the hot rads only having the lockshield open 1/4 of a turn, this rad is still not getting hot at all.

When the heating is on, if I have the TRV set to high and the lockshield open, I can hear that water is trying to be pumped round the rad, and occasionally, we've had a high pitch whistle coming from it.

There's no air in it as I've tried to bleed it, and only water comes out.

With the TRV closed, if I try to bleed it, water comes out slowly, which says to me that the flow isn't blocked at the lockshield end, and if I open the TRV, the water sprays out of the bleed valve, so it doesn't seem to be blocked at the TRV end either!

So all of this has left me at a bit of a loss - if the water is able to flow, I would have expected at least some warmth coming into the rad, but it's stone cold, and both the pipes leading to it are cold too!!

I think my next effort tonight will be to close off all of the rads (via the TRV's, and also close the one in the hall too), and just leave this one open and blast the heating on, with the hope that there's some sort of blockage and this may clear it?

Any thoughts / suggestions??

Thanks!

 

[denso13]

I think my next effort tonight will be to close off all of the rads

Yes try that, leaving the problem one open. If it works you most likely have a balancing problem, if it doesn't there is a flow/blockage issue.

 

[neiltheplumber]

As you say, try closing of all rads except that one. Next i would try closing off problem rad and removing rad, then pull some water off each valve by opening valve up and running to a bucket. Also while youve got the rad off take outside, turn it upside down and stick a hose in one end and bast cold mains pressure through it to make sure flows through!

Not sure if you said its a combi or system boiler?

 

[JohnD]

turn off ALL the hot ones like you said. If that single one doesn't get hot, it has a blockage or a stuck valve. Until you do that, it's guesswork.

If it does, you need to put more effort into balancing.

When did it last work properly?

edit:
too slow