One cold radiator

[rcolley]

I drained the system last week to fit TRVs. Since then one radiator has not worked.

There is no air in the rad. The TRV is on the cold end of the rad. I tried turning off all the other rads, this made no difference.

Drained the rad and disconnected valves. Water runs through the hot end valve. Remove the cold end (TRV) valve and nothing runs through it. So water can get in but not out.

Any suggestion?

 

[twgas]

It's blocked, needs cutting out and cleaning, or replacing.

 

[rcolley]

It's blocked, needs cutting out and cleaning, or replacing.

Thanks for that, but what is blocked. It is not the rad itself. It used to work before I fitted the TRVs but it was always the coldest on the system

 

[twgas]

Did you actually remove the trv from the pipe, as I assume from your first post, or did you just open the trv and get nothing.
If it's the first scenario - the pipework is blocked. If second could be trv or pipe.

 

[rcolley]

Did you actually remove the trv from the pipe, as I assume from your first post, or did you just open the trv and get nothing.
If it's the first scenario - the pipework is blocked. If second could be trv or pipe.

Yes, I removed the TRV from the pipe. Nothing flows out of the pipe. So I suppose it must be blocked, but I cant really see how it came to get blocked. All I did was drain the system & fit valves.

Trouble is it's an 8mm system and the pipe disappears into the concrete floor, no idea where it goes.

 

[jackthom]

If it's an unvented system with a pressure gauge, you could try using the filling loop to temporarily increase the pressure to around 2 bar and see if that starts to shift the blockage.

 

[adlplumbing]

if it`s vented try turning of flow water to the cylinder at gate valve next to three port so you send more water around heating system and turn all other rads off and turn the pump up to max and might blow out the blockage