Air in one radiator

[dstewart]

Hi,

I keep getting air trapped at the top of one radiator. The pump is vertically mounted and therefore self bleeding.

Also, I don't know if this is related, but when the heating comes on you can hear the water entering or priming the system up again.

Also, when the boiler has been running water to the radiators and it switches off you get a thump which I believe is coming from the tank up stairs.

Can anyone explain potential causes or tests regarding the air in the radiator and the occasional thump which may be an unrelated issue.

Thanks

David

 

[ChrisR]

Look at tank in loft at pump start and stop. Looking for water coming out of vent into tank.
Hold tumbler of water under vent when pump starts- does it suck the water up the vent?

Either of those are due to bad system design, or sludge/scale deposits, and will entrain air into system.

Otherwise you have corrosion going on producing gas - add inhibitor.

 

[dstewart]

Thanks ChrisR. Your expertise is much appreciated.