Old system with potterton floor stander on GND floor gravity fed cylinder pumped central heating. All radiators get hot apart from one (has previously worked fine but has not worked for about a year unused room for when kids come over)
House is solid floor so downstairs is via drops from 1st floor. Cracked open the flow and drained the radiator and took off the wall and flushed with hosepipe. With the radiator off I got hot water from the flow valve, however on the return side I can remove the valve and get barely a dribble.
Prior to taking off radiator I turned all rads off including lockshields and still no heat. Whilst like this I did get some pumping over in the loft from open vent only a very small dribble.
Emptied the header tank by removing a plastic fitting that had been cut in under the floor 15mm pipe where the header tank cold feed goes under the floor heading towards the boiler which is 7m away. Didn't get a gush of water from that either on the part of the pipe that is heading towards the boiler just a dribble but all radiator valves were off.
Put radiator back on and refilled header tank and bled the rest of the system first before the offending radiator with a small amount of air coming out of those radiators but bled normally. Moved to the offending radiator and that was slow to bled and didn't hear water gushing into it however got there in the end after turning boiler on and getting heat into rest of system. Radiator is now full but still no heat. Seems like the return pipe is blocked? All other radiator get hot.
I have access to compressed air could I give the return pipe a blast with that? Have some x800 but didn't know if any point in introducing that in case cannot flush it out and if no flow through radiator would it clear the blockage. There are two drain cocks on the low points for the drops for the gnd floor.
Thanks for any advice
House is solid floor so downstairs is via drops from 1st floor. Cracked open the flow and drained the radiator and took off the wall and flushed with hosepipe. With the radiator off I got hot water from the flow valve, however on the return side I can remove the valve and get barely a dribble.
Prior to taking off radiator I turned all rads off including lockshields and still no heat. Whilst like this I did get some pumping over in the loft from open vent only a very small dribble.
Emptied the header tank by removing a plastic fitting that had been cut in under the floor 15mm pipe where the header tank cold feed goes under the floor heading towards the boiler which is 7m away. Didn't get a gush of water from that either on the part of the pipe that is heading towards the boiler just a dribble but all radiator valves were off.
Put radiator back on and refilled header tank and bled the rest of the system first before the offending radiator with a small amount of air coming out of those radiators but bled normally. Moved to the offending radiator and that was slow to bled and didn't hear water gushing into it however got there in the end after turning boiler on and getting heat into rest of system. Radiator is now full but still no heat. Seems like the return pipe is blocked? All other radiator get hot.
I have access to compressed air could I give the return pipe a blast with that? Have some x800 but didn't know if any point in introducing that in case cannot flush it out and if no flow through radiator would it clear the blockage. There are two drain cocks on the low points for the drops for the gnd floor.
Thanks for any advice