After moving house a few months ago I have finally got round to trying to sort out a cold radiator problem.
It’s a traditional central heating system with a boiler, hot water cylinder, 2 feed tanks in the loft and a motorised valve. Most of the radiators including the cold one are being fed by 10mm copper pipe.
Things I have tried so far are
•Bled system including every radiator and the air vents by the cylinder
•Turned every other radiator off except the cold one. This made no difference.
•Remove radiator and flush
•Drained down entire system and filled back up x2
•Drained down and filled back up adding sentinel cleaner. Left this in the system for 4 weeks.
•Replace TRV on right hand side with a new non TRV (I couldn't get a TRV to fit the old size thread)
•Checked left hand valve (opened and hot water came out under pressure)
•Whilst the radiator was off I flushed it again. Whilst flushing I blocked the other end to make sure water was coming from the bleed screw hole.
Whilst the radiator was off I tested the valves again and the left one when opened shot hot water out under pressure but the right valve just trickled hot water out (which I assumed may be correct as I wouldn't expect pressure on both sides of the radiator).
When the radiator is connected and the system is running the valve on the left (the one that shoots out hot water under pressure) is cold but the right (the one that dribbles out) is hot.
Any help would be great as I'm out of ideas. I would rather try and fix this myself if possible but I guess I’ll get the answer of needing a power flush. I would rather avoid this at the moment as I want to get a new boiler before next winter and would update all the TRV’S and get it flushed out at the same time.