Radiator hot at the top cold at the bottom

[beitou]

Hello.

does anyone here have any advice on this old problem. A plumber changed an old 1970 style radiator for a new single panel one with a new thermostatic valve and a new valve on the out let end. The plumber did not open the outlet valve so the rad did not heat up. I contacted him by phone and he told me to fully open the outlet valve. I did this and once the rad started to heat up he said it was sortted, stupidly I took him at his word and did not wait for the rad to heat up fully. 3 days ago I put the heating on for the first time and after an hour and when all other rads are hot the changed one is warm at the top and cold at the bottom. the outlet valve is fully open and the inlet thermostatic is turned up to 5. The plumber is not answering his phone or replying to texts so it looks like it is up to me to fix and i cant afford another plumber. oh it is an upstairs rad. Any advice hep or suggestions would be most welcome as I am at my wits end with this saga.

thanks in advance

Beitou.

 

[tilly10]

Might be an air lock... have you tried bleeding it?

 

[beitou]

Might be an air lock... have you tried bleeding it?

Yes, no air in it at all, warm water runs out as soon as I open the bleeding valve.

 

[45yearsagasman]

One or two pipe system? Bit more system info would help.

 

[beitou]

One or two pipe system? Bit more system info would help.

Not sure of the difference, I am a complete novice, posting on here to try to understand what i have to do to fix it without paying another couple of hundred quid, please presume I am a moron and ask any questions that you feel might help.

 

[flameport]

Turn all of the other radiators off (or as many as possible). Does this make a difference?

 

[beitou]

all the other radiators are turned off and cool but it makes no difference, still warm at the top and cold at the bottom. Oh it is a single pipe system