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is it a blockage/ isn't it a blockage, that is the question.

Posted: Fri Oct 10, 2008 10:58 pm
by AdamsHeating
Hello,

I'm stumped and it is probably quite simple! I went to a job today, Worcester Bosch Greenstar junior 24i combi.

Hot water - check
Call for heating - check ... but wait a minute... no heat from the rads...

after about 20 seconds the central heating cuts out but doesn't go to fault code. The diverter valve is fine doing its job.

I put the big kettle into service mode to fire up central heating on full blast, comes on for 20 seconds and goes off, doesn't re light, no fault code.

The pump is red hot, the flow pipe is red hot, the return pipe is ice cold, is there a blockage?

I know i'm being an amateur here. My thoughts are it is blocked somewhere on the flow pipe. Pipes start at 22mm and are on Microbore to all the rads, not all rads have TRV's and all lock shields open. I emptied out the system, filled her back up, still nothing. I haven't got power flushing equipment so i'm uncertain how to clear it now even if it is a blockage. HELP!!!

Goes to prove that even though I can fit them, doesn't mean I can always fix them!

Cheers for help,

AH.

Posted: Sat Oct 11, 2008 7:33 pm
by nitro23456
gotta be a blockage or airlock really.

Posted: Sat Oct 11, 2008 8:37 pm
by Steve the gas
Take the big screw out of the pump for a minute whilst its running

Posted: Sun Oct 12, 2008 12:18 am
by screech
i've had pumps pack up on these without a fault code coming up

Posted: Sun Oct 12, 2008 12:48 pm
by htg engineer
If all radiator valves are open, boiler flow and return isolatio valves open and you have vented the pump.

I'd be looking towards the pump being the fault, it may be a broken impeller or just a faulty motor - enough to circulate the water around the boiler for the hot water but not for the heating.

htg

Posted: Sun Oct 12, 2008 4:55 pm
by AdamsHeating
cheers for the help you lot, I'll check the pump and see if that is playing up.