hot water but no heating

[mrminto]

Valliant old combi bolier, we had just a leak repaired and the system was drained down.

now the hot water fluctuate from hot to cold and there is no central heating. Bolier makes strange noise (pump?) that did not do before.

any idea?

 

[gas4you]

Could just be airlocked in th boiler. Is the auto air vent loose and working?

 

[mrminto]

what is auto air vent?

when i turn on and off it makes a lot bubbly noises

 

[gas4you]

Certainly sounds air locked then. Auto air vent is often fitted on top of pump or at top of boiler, depending on model etc.

Looks like a small canister with a plastic knob on top. Could have jammed shut with scale etc.

 

[bobbo85]

Is pressure up to 1 1/2

 

[mrminto]

fantastic it worked
Thanks

 

[bobbo85]

Have you vented rads ,make sure you keep pressure up when doing it , do it when pump is off ,so dont run boiler