Having to vent pump every time I turn heating on Help and information on all topics relating to your central heating, air conditioning and ventilation issues.

[gazzaman]

Every time I turn the heating on I have to release air from it by the front screw. the heating then works fine and even if turned off for a couple of hours and back on its ok.
but if turned off over night I have to vent it again !
is the pump drawing air in or is the air getting in else where ?
I have a grundfos 15/60 set on setting 1

[gazzaman]

Hello again.
I have now discovered that the heating works fine until hot water is also turned on !!
then all downstairs radiators start to gradually cool down !!!
then if turned back to heating only I have to release the air from the pump !!
Am I right in thinking that is NOT the pump at fault and air is getting in from elsewhere on the Hot Water side of the system ??

[Gordon S]

I had a similar problem with needing to vent the pump all the time.

It turned out to be a blockage between the F&E tank and the pump. There was no flow coming through to top-up the system.