Radiator only half hot

[Coxgc1975]

Hi all.

I live in Germany and have a communal heating system. The radiator and n my lounge has an entrance with TRV and then an exit (pictured). My problem is that this year only the first three bars of the radiator are getting hot. The rest get nothing g. There is no way of bleeding the radiator. If I turn the valve at the bottom to the right no water seems to flow, it seems to shut off. If I turn to the left the valve seems to open and water flows (I can hear it) but only the first three rungs get hot. Any ideas?
Thanks in advance.
[automerge]1577793219[/automerge]

Hi all.

I live in Germany and have a communal heating system. The radiator and n my lounge has an entrance with TRV and then an exit (pictured). My problem is that this year only the first three bars of the radiator are getting hot. The rest get nothing g. There is no way of bleeding the radiator. If I turn the valve at the bottom to the right no water seems to flow, it seems to shut off. If I turn to the left the valve seems to open and water flows (I can hear it) but only the first three rungs get hot. Any ideas?
Thanks in advance.

 

[SimonG]

Pretty poor way of connecting up the radiators.

The top connector may have had a spreader pipe to carry the water further along the radiator. If it did exist, its possibly corroded or come loose.

Waters dead lazy, will always take the easiest route.

Ideally the return would connect into the opposite end of radiator at the bottom.

 

[snowhead]

There should be a Bleed valve at the top, opposite end to the thermostatic valve, it's not painted over is it?

Have you unscrewed the thermostatic head to see if the operating pin is stuck?

How far are you turning the bottom valve open?

 

[John.g]

Your rads are plumbed TBSE (Top & Bottom Same Ends) v/vis TBOE (Top & Bottom Opposite Ends), it might seem a bit strange but there doesn't seem to be a huge difference in the (theoretical) outputs, the important thing is that the hot (flow) is on the top in both cases. There certainly should be more than the first three bars getting hot. As suggested, try and locate the air vents (if fitted?) and ensure the TRV & outlet are fully open.

 

[Chuck]

Any ideas?

Another possibility...

If it's just this radiator that has the problem, the TRV may not be opening full due to corrosion that built up while it was shut over the summer. Take the thermostatic head off the valve and see whether the operating pin moves in and out over a decent distance when depressed and released. By repeatedly pushing the pin down and releasing rapidly you may be able to free it.

 

[centralheatking]

You might also turn the lockshield valve (non trv) to close and open it by 1 turn this will stop the water taking the easiest route, gradually open it up 1 turn at a time to get optimum heat all accross the rad.
However if it is sludged up then the sludge will be slow/no flow region. centralheatking

 

[Coxgc1975]

Thanks to everyone that replied. Frustratingly and surprisingly there is no bleed valve on the radiator at the opposite side of to the TRV, it’s a sealed end.
I turned the non trv valve closed for a few minutes and then opened it one turn as centralheatking suggested. Eventually (after a few hours the entire rad became warm). Didn’t have the rad on yesterday but have turned it on today and it gets hot as it should do in normal time.

Many thanks for the suggestions everyone.
Happy new year.