AAVs - why do they fail so much?

[Roger Welton]

Fit Spirotops the water level is well below the valve so tends not to suffer so much with dirty systems.

 

[Jimbob]

I agree, I try to leave them open when commissioning, then after I'm happy there's no air, I tend to shut them.

And being directly above the main heat exchanger can't help on the grants.

You can get better quality aavs, like the solar ones. Never really worth it though as things like this gives us work

 

[dancinplumba]

Takes a while to get all the air/gasses out of a sealed system

 

[Roger Welton]

Takes a while to get all the air/gasses out of a sealed system

Same as me after a curry

 

[dancinplumba]

Wondered why there's always a dark toxic cloud over Somerset

 

[WHPES]

I always have a load of AAVs in the van and if I come across one on a service that looks dodgy I replace it as part of the service.

 

[Sparkgap]

Used to use Winns AAVs, built like battleships and lasted for millennia! Cost a packet tho'! Now use Spirotop and have virtually no problems. (touch wood!)

 

[MarkOil]

I've seen recently that new Grant boilers now don't have AAV's! they have brass air "pips" like on radiators.
What I was wondering is; would it be worth keeping a few in my van so I can fit these instead of changing the AAV's for another one that is just going to leak again??

 

[CXR100]

i remember seeing the mr combi dvd whilst in collage, and remember him pointing out buggerd auto vents and always blaming it on undersized expansion vessels (or obviously undercharged ones) , his advice was to isolate. completly drain the boiler, leave the drain off open then fill the boiler so that clean water would flow thru it and out the drainoff to flush it. then pour a jar of x200 inside it and recharge or fit a bigger expansion vessel , before fitting a new aav!!!

 

[kimbo]

I've seen recently that new Grant boilers now don't have AAV's! they have brass air "pips" like on radiators.
What I was wondering is; would it be worth keeping a few in my van so I can fit these instead of changing the AAV's for another one that is just going to leak again??

The new grant combi has 2 aavs and the ordinary boiler has a radiator type manual one on the return.