AAV In Loft Leaking...

[danielson]

I have an AAV connected to my stack in the loft and it has 'ventapipe 50' markings on the top. I noticed some water on the top of the pipe where the seal is on the pipe and wondered how it was getting there. I have then looked up into the AAV and there is quite a bit of condensation (well i think its condensation?!) on the inside of the valve. I have some pictures below showing this - I don't know if this is normal on them or not?? The nearest branch connection to this is approximately 2.5m below the AAV in the bathroom below..

 

[WC1]

Looks like warm moist air is leaking back through the aav and condensing on it. Suggest you replace the aav.

 

[danielson]

Looks like warm moist air is leaking back through the aav and condensing on it. Suggest you replace the aav.

Thanks will have a look into getting another one - I see this one has actually got poor reviews with the seal failing. Think it’s McAlpine so may look into another manufacturer of them this time.

 

[Roy_66]

Looks like you have enough space to fit a simpler looking one.

This unit looks like a valve plus an adapter. Is one idea for applications where you are short of headroom (e.g. no soffits or low angle roof pitch so not enough space under the felt.) In that case you can rotate it towards Centreline of the house to gain a bit of head space?

Anyhow, simplest to change yours.

Cheers,

Roy

 

[WC1]

Look for one with rubber fins (but not this awkward looking macalpine job)
If it doesn't have fins you'll need to glue it to the pipe with solvent weld cement.
(And you know how complicated that can get )

 

[oz-plumber]

That's why vents are designed to go outside, external of property, to atmosphere.

Never liked them - installed about 10 in 25 years in the game

 

[AWheating]

Get a polypipe one. Comes with a poly insulation cap to stop it freezing. Or maybe the flowplast external one which is OK down to - 20.

 

[danielson]

Get a polypipe one. Comes with a poly insulation cap to stop it freezing. Or maybe the flowplast external one which is OK down to - 20.

Is this the one

Polypipe 110 mm PVCu Grey Air Admittance Valve - https://www.mrcentralheating.co.uk/polypipe-110mm-pvcu-grey-air-admittance-valve

Would rather overkill it and have this one in the loft as I wonder if the low temperature is what causes the seals to go on the internal spec ones...

Look for one with rubber fins (but not this awkward looking macalpine job)
If it doesn't have fins you'll need to glue it to the pipe with solvent weld cement.
(And you know how complicated that can get )

Yes it certainly does - at least they seem to be PVC these AAV’s! I don’t mind welding one on if it’s going to give me a better fit and therefore seal.

Looks like you have enough space to fit a simpler looking one.

This unit looks like a valve plus an adapter. Is one idea for applications where you are short of headroom (e.g. no soffits or low angle roof pitch so not enough space under the felt.) In that case you can rotate it towards Centreline of the house to gain a bit of head space?

Anyhow, simplest to change yours.

Cheers,

Roy

yes its not needed in my loft as I still have some roof space for a bigger adapter. I guess that’s what the previous plumber had in their kit at the time!

 

[WC1]

Not sure why they fail. It's very rare indoors. I have always assumed dust and cobwebs get in the moving parts.
The one from mrcentral is a solvent weld type.
Fyi as far as I'm aware 110mm plastic soil pipe and fittings are all ABS so should be fine.
I think you're right the last one was made up from what was to hand.
I don't have a preference for manufacturer but those without the shroudy bit are useful if the pipes got too close to the wall and the shroud would foul on the wall - not significant in your case
Have you tried disassembling and cleaning the valve. Some types are possible to clean and as it clearly isn't doing what it should then why not have a go.

 

[danielson]

I managed to unclip the valve to reveal the seal which to me looks ruined - it seems a pretty common problem on this particular part by McAlpine. Would this be why I am getting condensation leaking onto the soil pipe in the loft as the seal is not working properly?

 

[WC1]

That is very likely. Get rid imo. New aav.