Zehnder (etc?) plenums nonsense design..?

[Cognis0]

I've just started installing a Zehnder MVHR system and I'd be grateful for advice/observations about fixing the plenums/valves. These plenums have a flat top section which need (it seems) to be fixed to the underside of the floor above! I'm not sure what the designer had in mind, but can't see how it is feasible to fix the plenums in place in this manner.

Once the plenums have been fixing between the joists I then have to fix galvanised "Circular Long Threaded Mounting Frame Vent Galvanised VRGLs" into the plenums (adhesive?) for the valves to screw into..

The whole design is nonsense ~ surely it is not beyond the wit of man to design room extract/intake valves that can be installed entirely from below ceiling level once the 75mm flexible ducting has been fed through from above?

[JohnMo]

We just added noggins between our joints, where needed. All done from below.

 

The terminal/valve just slips in the 125mm dia plenum. You may have to remove later so no don't glue.

 

You may have to upload some photos - no real idea what you have or why it's difficult.

 

[ProDave]

Mine, from BPC, I forget the make.

 

 

Fixed from below ducts just push in, cut to length after plasterboard fitted and the outlet just pushes on.

[Kelvin]

I have the same and I don’t recall any difficulties installing them. I added offcut noggins here and there to give me something to fix them to. 

[Mike]

2 hours ago, Cognis0 said:

I've just started installing a Zehnder MVHR system and I'd be grateful for advice/observations about fixing the plenums/valves. These plenums have a flat top section which need (it seems) to be fixed to the underside of the floor above!

The fixing brackets are reversible, so you also have the option of fixing them to the top of the ceiling - for example on to battens spanning between joists.

 

2 hours ago, Cognis0 said:

Once the plenums have been fixing between the joists I then have to fix galvanised "Circular Long Threaded Mounting Frame Vent Galvanised VRGLs" into the plenums (adhesive?) for the valves to screw into.

Not if you're using Zehnder vents - they just push into the plenums. But if you're mixing and matching brands (VRGLs are a Lindlab compnent?) then you'll need to work it out.

[Cognis0]

On 15/12/2024 at 11:03, Cognis0 said:

I've just started installing a Zehnder MVHR system and I'd be grateful for advice/observations about fixing the plenums/valves. These plenums have a flat top section which need (it seems) to be fixed to the underside of the floor above! I'm not sure what the designer had in mind, but can't see how it is feasible to fix the plenums in place in this manner.

Once the plenums have been fixing between the joists I then have to fix galvanised "Circular Long Threaded Mounting Frame Vent Galvanised VRGLs" into the plenums (adhesive?) for the valves to screw into..

The whole design is nonsense ~ surely it is not beyond the wit of man to design room extract/intake valves that can be installed entirely from below ceiling level once the 75mm flexible ducting has been fed through from above?

...I should have said that this is retrofit into a 16th century cottage, not a new build before the ceilings go up!!

[JohnMo]

Where are your ducts going - photo?