Should water shoot out of auto air valve?

[Neil Carroll]

I've a combi boiler with an auto air valve, the cap is missing, it's been missing for years, when I press the valve down water shoots out, otherwise it doesnt leak at all, I'm assuming this is faulty, I'd appreciate any advice, I can change it if needed for about £20, it's not in the combustion chamber. Also if there is a problem and I manage to open it up and clean it and release it if seized, rather than buying a new one can I just replace the cap? Is it literally like a car tyre cap?

Thanks

 

[terryplumb]

Quite normal for water to come out if you hold the valve open/ press it.
A bit like a car tyre valve ,if you press it, air comes out !

 

[Neil Carroll]

thanks, I was expecting air, not water!

 

[terryplumb]

The valve automatically expels air, which is pushed out by the water,and closes before water spews out.

 

[gas112]

are you sure its on an auto air vent and not an expansion vessel

 

[robinbanks]

I can change it if needed for about £20,

Show us a pic of it first

If water comes out of an aav, it's doing its job of expelling air that collects in it. Normally it's full of water and is a high point in the system that collects air, which it then releases. As the air comes out, water comes in to take the air's place, and the presence of the water shuts the valve again

If air comes out, it's not auto bleeding it

 

[Madrab]

when I press the valve down water shoots out,

Cant say I've come across many auto air vents with a valve in it that you can push down (Shraeder?), that would defeat the purpose of it being an 'auto' air vent.

Most do have a dust cap that is loosened and any air is then expelled 'automatically' by the internal float dropping. When there is enough air in the top of the bottle the spring pushes the float down and releases the air, once the air is expelled the water fills back in and pushes the float back up and shuts the valve.

As suggested, sure it isn't the expansion vessel? A pic would help

 

[ianmcd]

it is not an air vent that you are messing around with

 

[mattylad]

Need pictures.

Not puppies, the neighbours wife or where you went on holiday last - the valve your referring to