How high should the holes be to outside for the mvhr

[CalvinHobbes]

Help, we got a plan from bpc for a quiet vent axia but it doesnt give an elevation for the in and out. The brickies are near there and I was going to get them to put in 2 pipes to save the spot for the vents. Is it joist level?

[Conor]

Depends entirely on where the unit will be situated, the required height above / side for the duct work etc. Ideally they need to be 2m apart to prevent circulation. Not as simple as it sounds as depends where the exhaust / supply points are on the unit and what other duct work and services you need to work around. 

 

I stuck two in at that stage and ended up moving the unit and having to core out new holes.

[Temp]

Keep them upwind of you boiler flue. Ideally on a different wall around the corner.

[CalvinHobbes]

Thanks Conor, BPC have given us the layout so I am fairly confident it should stick. It was just the elevation I was unsure of - thinking just under ceiling height will do. The layout said they had to be 1.5m apart. The other thing was the actual pipe to put through the 20mm cavity walls. It says on the plan it needs to be 180mm in diameter so tried to get one locally today - no joy. Gonna have to go to BPC in Larne tomorrow morn to get some. Bah.

Edited June 20, 2023 by CalvinHobbes

[CalvinHobbes]

3 minutes ago, Temp said:

Keep them upwind of you boiler flue. Ideally on a different wall around the corner.

Thanks doing an ashp nearby, would that be ok?

[Temp]

Just now, CalvinHobbes said:

Thanks doing an ashp nearby, would that be ok?

 

Shouldn't be a problem. 

[Conor]

13 hours ago, CalvinHobbes said:

Thanks Conor, BPC have given us the layout so I am fairly confident it should stick. It was just the elevation I was unsure of - thinking just under ceiling height will do. The layout said they had to be 1.5m apart. The other thing was the actual pipe to put through the 20mm cavity walls. It says on the plan it needs to be 180mm in diameter so tried to get one locally today - no joy. Gonna have to go to BPC in Larne tomorrow morn to get some. Bah.

Lindab have all that sort of stuff in stock. I'd leave 200mm dia holes and then foam in round. You want to leave a bit of a fall to the outside in case wind driven rain gets in.