air in central heating, causing havoc!!!!

[fallguy]

having trouble with air in the central heating system, its a vented system and i have a couple of rads that require bleeding frequently

in conjunction with this, the overflow from the header tank is throwing out water

could there be a problem where water is being displaced by air in the system is being forced back into the header tank, hence the overflow

float valve all in order, pump facing the motorised valve

any ideas???

 

[rebuke]

Does water come out of the overflow continuously (i.e. even when the system (boiler / pump etc) is off)?

If so, it might mean you have a punctured coil in your hot water cylinder (assuming you have one), which is allowing water from the cold tank to cycle through into the central heating system. It doesn't explain the air, but I guess the combination of that water coming in under pressure from gravity and the pump running could cause it somehow...

 

[fallguy]

no its not continually, just occasionally when the boiler/pump is running

had the experience before and it disapperead, now its reared its ugly head again

will have to monitor it more at the header tank to see whats going on