glow worm 24 combi problem

[maikz]

Hi.
Today I was doing some work in customer house and I was asked to check why 1 radiator doesn't heat up. They have glow worm 24 combi (can't remember exact one - looks cheap and cowboy fitted) and after bleeding and trying to balance radiators, I noticed that return and flow valve are wrong way around(I guess). On left hand side(only side where pipework gets hot) valve there's arrow that points towards boiler(if it's flow, then it should be other way around).
So my question is, could it be the valves wrong way and are the valves one way only(doesn't let much water through other way??). Thanks.

 

[Halesowen1]

Dont think they would be one direction only, so dont think thats your problem. Left side is usually Flow.

 

[maikz]

Dont think they would be one direction only, so dont think thats your problem. Left side is usually Flow.

Thanks, I guess I have to check if pump is pumping at all, might be stuck. I was hoping that it's valves, would make life easier. Don't want to get too involved.

 

[Halesowen1]

If it looks that rough, may well be the rad has never worked due to dodgy workmanship, piping problem etc.

 

[maikz]

Had another go today. Checked pump, all good nothing broke(took it off twice). Valves are not one way either, so that can't be the problem.
It heats up on flow side and heat slowly follows the pipe towards radiator, but there's no heat coming back - return pipe is cold. It only got hot when I bleed the system and water was coming through from boiler(I guess). Could there be blockage after the pump in boiler pipework? Or any other ideas, not sure if radiators have worked ok before.

 

[mak]

are the TRV'S sticking?

 

[maikz]

are the TRV'S sticking?

There's no trv-s, and valves seem to work ok, none seems stuck.