Automatic Air Valve

Water is dripping out of the top of my automatic air valve (combi boiler), resulting in a drop in pressure. What can I do to resolve this?

The obvious answer is to change it?

Or have I missed something?

Tony

Thanks for the reply Tony, but i was hoping for ideas and suggestions of what may be causing the problem.

In general what are you looking at (money wise) to replace the part?

Can you not just strip it and replace the broken washer or whatever the problem is?

Or is this not praticle, if it is, would you have to drain the system or is there a valve that stops the water gushing out when the Auto Air Vent is removed?

Scale and muck builds up on the valve seating causing it to leak.

New vent likely to be between £10 -£15 unless a Chaff in which case £25.00.

Not worth trying to clean it.

De-presurise the system and replace the vent, some boilers require pump removal, some boilers have the vent within combustion chamber so really a corgi job.

Tell us the boiler make/model.

If I was replacing the aav I'd also check the pre-charge on the expansion vessel whilst the boiler is un-presurised. About £60 including full safety check. I buy vents in bulk at £4.00 a go.

We would do it as part of our diagnostic check which includes a service and performance test.

In London we would charge £84 plus about £12 for the part.

No professional would ever do anything apart from change one unless he had run out of spares in which case he might clean it until he can return to replace it.

Original boiler AAVs require the boiler to be drained the below the level of the AAV. There are some replacements designed for systems which have a built in valve to enable the AAV to be changed without draining.

Whilst almost everyone else would just change it for a new one, I can only immagine that your apparent interest in the insides is because you dont even want to pay about £12 for a new part?

Tony