rad problem

[john1045214]

help. i have moved into a new house recently, i drained the central heating system to lower a radiator, i didnt alter any pipes, just lowerd the rad. the system has a conventional boiler with a f&e tank. i drained the system from the rad which is in the extention downstairs, i refilled the system via the f&e tank, all rads bled ok, all rads work ok, except the two in the extention (down stairs). its been like this for 6 months now, i think they are fed from a vertical drop in a partition wall from the extention upstairs (rad is fine here). if i turn all rads off except extention downstairs feed pipe gets hot (very hot), nothing on the return though!! 1 rad did dtart to work (nearest to vertical drop in partition) remaining rad (last in loop) got nothing. i tried to bleed both, now both not working again. i have had the coupling off under the floor and both feed & return are free from blockage, valve on rads are also operating correctly. have i got a monster air lock? should i refill from rad in the extention doenstairs using mains pressure to try and clear? thanks for any assistance

 

[seco services]

have you tried removing the return from rad and opening the return valve over a bowl or connect it to a hose and let it run.

 

[john1045214]

hi, yes, the return has run for some time, reconnected and bleed the system - still the same - the system worked ok before drained the system and moved the rad upstairs, like i said, i didnt change any pipework, just a simple moving of the rad - or so i thought !!!