is it a blockage/ isn't it a blockage, that is the question. Help and information on all topics relating to your central heating, air conditioning and ventilation issues.

[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.

[nitro23456]

gotta be a blockage or airlock really.

[Steve the gas]

Take the big screw out of the pump for a minute whilst its running

[screech]

i've had pumps pack up on these without a fault code coming up

[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

[AdamsHeating]

cheers for the help you lot, I'll check the pump and see if that is playing up.