Grant VTX Combi 21 air in hotwater heating side

[epictcr]

Hi,
I'm puzzled, I think it should be fool proof. having installed my new Vortex Combi, and associated pipe work I am pleased with the operation of the central heating.
however! the separate pump that circulates in order to provide hot water groans and gurgles while heating its reserve.
I'm confident it is not air in the actual hot water that delivers from the taps as I never get any spitting while running the tap.
I drained down the boiler from the right hand drain tap and refilled recently while bleeding from both auto air bleeds and the manual one. this helped greatly and I thought that problem was solved.
however in the past 3 weeks it has become steadily noisier again.
I have not observed any noticeable drop in system pressure.

suggestions? faulty bleed valve allowing air back into the system?

any ideas gratefully received.

 

[dcawkwell]

Sounds like air in the boiler in the heat store.

 

[epictcr]

Pretty sure it's. Air in the how side, don't understand how it gets in there, rads have no air in, and the entire system inc pipes is brand new. Do auto air valves fail?

 

[dcawkwell]

Pretty sure it's. Air in the how side, don't understand how it gets in there, rads have no air in, and the entire system inc pipes is brand new. Do auto air valves fail?

Yes auto air vents fail.
If you unscrew the air vent until water or air starts to come out.
There should be a manual one or automatic one.

 

[oilhead]

There are 3 a.a.v;s on this boiler that could be at fault. If you are sure that you have evacuated the air, close off the vents for a day or two and see if you still get air. If not, then you can leave them shut, occasionally checking for any air, or change all three and operate normally.