DIY Doctor UK DIY Forums

hi, system is 25+yrs old, new boiler 13 yrs ago, new pump, 2007. all working aok except rad in bathroom. was told long ago that it was intended to stay on when c.h was off. ie as a drier. so had to turn both valves off in summer. this winter its been cold so bled it, no air just water coming out, takes ages for it to get even lukewarm, but have to keep bleed valve open.
decided to undo bleed valve and drained off about 2 gals, pipes got red hot fairly quickly, but after i put bleed valve back in, after 1/2 hr rad was cold again. tried various ways with inlet/outlet valves but no joy. not huge problem for us but just annoying. any ideas folks, cheers...

boomer39,
Sounds like you have an airlock, close each of the valves in turn and drain off the 2 gallons again each time, hopefully this will clear the airlock.
end

Sounds like you have a flow problem. When you ensure a flow by opening the bleed then you get a hot rad but when you stop bleeding the rad it goes cold. Most likely that the vlave on the return side of the radiator is not open - have you checked that both valve are open?

Hope you can get it sorted.

Mr Fixit

has this radiator ever worked?

one radiator on systems such as you describe is kept permanently on to always allow water to circulate between the flow and return of the boiler..In the event that all other radiators (or the timer) are turned off the pump will still run and have a circuit to complete without back pressure.

two scenarios spring to mind - the radiator has been connected to the same pipe, which means it will never have worked, but will get hot when you let some hot water into it. This is unlikely to be the case.

More probable is that one of the valves has blocked - check to see if they are both fully open - try opening and closing fully a few times since this may unblock it. If no joy, then turn off the valves and disconnect from the radiator and open each one in turn to check that water comes out of both. If one doesnt let water out then this will need repairing or replacing.

If this doesnt work, then dunno!!

Hope it helps

thanks folks. rad has worked but never got a shot as all the others,9 in all. only had this problem this winter, fairly sure both valves are opening but that sounds the best scenario, will try that later. as i said its not a great problem cos the house is quite warm all day and night but its annoying,f you see what i mean. thank you all once again, will keep you informed
paul kelly, ynwa...