Push button bleed valve on a towel radiator

[MikeW1959]

Hi, My son in laws bathroom radiator isn’t getting hot, the bleed valve is fitted at the back of the rad facing the wall, it has a plastic locking nut and a push button, if I hold the button down, water comes out and the bottom R/H valve becomes hot/warm, however when I stop bleeding the rad it starts to cool straight away, he tells me that it used to work perfectly after it was fitted, which was only about 4/5 months ago, has anyone got any tips I can try please.

 

[just pumps]

Bottom L/H valve closed?

 

[MikeW1959]

Hi, No I’ve checked that, it’s an allen screw and I’ve tried it fully clock and anticlockwise

 

[oilhead]

Does it bleed with one valve at a time closed(ie through both the flow and return)? Try that and bleed about 2 pints at a time.

 

[martygturner]

Has it got a trv fitted

 

[MikeW1959]

@oilhead I’ll give that a whirl tomorrow, thanks for the tip, I’ll let you know.
@martygturner no TRV fitted, just one you can turn off/on by hand and another with the allen key fitting

 

[Harry Bloomfield]

Have you tried turning all the other radiators off, just leaving that one on?

 

[MikeW1959]

No I haven’t Harry, I’m going round tomorrow to have a look, I’ll also try your advice, will let you know, thanks for the reply

 

[MikeW1959]

Just a quick update on my findings, thanks for the advice everyone who gave it, first I tried the turning all the rads in the house off, the rad still didn’t get hot, I shut the L/H valve off, the one with the allen key fitting, and opened the bleed screw, lots of water and under pressure, opened it and closed the R/H valve, opened the bleed screw and water just dribbled out, checked the boiler pressure and it was fine, removed the rad and opened the L/H valve slowly, very little water, I then foolishly stuck my long thin screwdriver into the valve opening, first the thick black sludge came out followed by lots of cold, pressurised water, every days a school day! Once again thanks to those who helped, much appreciated.