Any ideas? Unreliable heating.

[garyevans]

Thanks John. I have bled the rads but not emptied them per se - when you say 'no circulation or corc pump defective' what else could cause the 'no circulation'? The weird thing is that on Sunday after I changed to CP2 all rads were hot, same Monday but then Monday night the downstairs rads went cold. So that must be an airlock? But there is no air in rads! Given that we have had heat i would guess the pump valves are fully open.

last one - the screw in the pump to deblock - manual says to turn screwdriver anticlockwise, but youtube vids say ant and then clockwise? Is that a possible issue?

 

[John.g]

That makes sense, an airlock is a distinct possibility, the only way ("new fresh") air can get into the system is through the air vent, the pipe that bends over the F&E (small) tank. Try and tape a container of water (say a few litres) under this vent with the open end immersed in the water and watch it while starting/running the pump or as I suggested earlier on, just get someone to do as I suggested in post #15, do this first mybe.

 

[John.g]

last one - the screw in the pump to deblock - manual says to turn screwdriver anticlockwise, but youtube vids say ant and then clockwise? Is that a possible issue?

Don't think so, if it needed deblocking anyway you should get a LED alarm.

 

[EvilDrPorkChop]

Turn all the rads off downstairs bar one, get that one red hot. Turn it off. Turn next one on and repeat for rest. It's just airlocking that's all by the sounds of it. If valves are red hot to radiators, then sounds like air. You've not balanced up downstairs have you?

 

[garyevans]

Turn all the rads off downstairs bar one, get that one red hot. Turn it off. Turn next one on and repeat for rest. It's just airlocking that's all by the sounds of it. If valves are red hot to radiators, then sounds like air. You've not balanced up downstairs have you?

Yes, balanced all rads up and down a few times.

Had a plumber come round. He has checked the pump, the valves, drained the system, rebled the system, checked the feeder tank in loft and it is still the same. He is convinced there is a blockage in the 'return' feed pipe (I am not going to pretend I know what that is) and we need to do a powerflush.

 

[John.g]

Was the pump renewed without any drain down?

 

[garyevans]

Was the pump renewed without any drain down?

No idea sorry as I was not here. I reckon so as it was a British Gas engineer as we have the home care.

 

[John.g]

I don't see why anyone would drain down a system just to change out a pump, however we can talk till the cows come home but
I would go way and buy one of those cheap plug in energy monitors on amazon or where ever, remove the pump cable from the terminal box, Connect a 3 pin trailing socket into the terminal box where the pump was, put a 3 pin plug on the end of the pump cable, plug the energy monitor into the socket and plug the pump into the energy monitor and monitor the pump power, that will eliminate or not a pump problem to start with as these pumps have a very high failure rate or inconsistent performance even out of the box, the monitor is only £15 or £20 and very accurate.

 

[EvilDrPorkChop]

Yes, balanced all rads up and down a few times.

Had a plumber come round. He has checked the pump, the valves, drained the system, rebled the system, checked the feeder tank in loft and it is still the same. He is convinced there is a blockage in the 'return' feed pipe (I am not going to pretend I know what that is) and we need to do a powerflush.

Unbalance the downstairs ones, so they're open fully. Leave upstairs balanced.

 

[EvilDrPorkChop]

I'm guessing everything worked before new Pump OK?