Pro Combi 85 he leaking AAV

[RPDS]

Morning all. I've been to a call out where the customer was reporting water leaking from their 4 year old combi boiler after it had been running for 10 minutes or so.

Went to have a look and the pressure was at 2 bar as the filling loop was permanently on. Turned it off got the pressure down to 1 bar and tried it and sure enough after 10 minutes running, water was spurting from the aav. Thinking it was a stright forward fix, I've replaced the aav, and cleaned off the seating, but it does exactly the same thing.

I've rung the technical helpline and the guy basically said that shouldn't happen(!) and the boiler's knackered and needs replacing. I can't help thinking that he's fobbed me off a bit and there should surely be a fix for this, however I'm stuck for ideas and don't want to go throwing money (other peoples) at it if it really is knackered.

On a side note that may or may not be related, sometimes the burner will go out before the aav leaks (and when I say leaks, it pours) fan still runs etc but I get a green flashing light every second ish.

No sign of water coming out of the prv which I would have expected with the filling loop permanently on.

I am gsr but not much experience so any help would be appreciated

 

[wards]

is the pressure gauge giving the right reading?check expansion vessel also.

 

[RPDS]

pressure guage and expansion vessel seem fine

 

[jtsplumbing]

Have you replaced the PRV ? it may be jammed shut !

 

[RPDS]

It starts leaking from the aav at about 1.5 to 2 bar and the prv wouldn't kick in until 3 bar would it?

 

[GrahamM]

IIRC most AAV's are rated to 10bar.
If you replaced with new AAV, it must be faulty in my opinion.