Some questions on MVHR installation

[TonyT]

It’s always easier to get a timber fixing on these, so it pays to install a plywood pad in the ceiling, just similar to putting plywood behind walls for radiators to get decent fixings.

[MikeGrahamT21]

42 minutes ago, MJNewton said:

 

They were a reasonably good interference fit but, yes, for completeness I did run some aluminium tape around the join (on the inside as access was easier). 

 

This is a BC requirement, has to be aluminium tape

[PeterW]

53 minutes ago, MikeGrahamT21 said:

 

This is a BC requirement, has to be aluminium tape

 

Is it ..?? Where’s that documented..? I thought it said the ducts had to be sealed correctly which for the Lindab stuff is an internal rubber seal. 
 

 

[MJNewton]

34 minutes ago, PeterW said:

 

Is it ..?? Where’s that documented..? I thought it said the ducts had to be sealed correctly which for the Lindab stuff is an internal rubber seal. 

 

On the Domus plenums the interface between the plenum and the 125mm pipe doesn't have a rubber seal - it's just an interference fit between the plastic surfaces. Reasonably airtight but prone to slight movement so I think tape is worthwhile (I've got a feeling the instructions advise the use of sealant). 

Edited January 27, 2021 by MJNewton

[MikeGrahamT21]

I can't find where i read it now. I know BPC state to use aluminium tape: https://www.bpcventilation.com/media/download_documents/bpc_new_installation_manual_2019_printer_version_secured.pdf

 

I have read it though I promise, BCO's look for the tape on the joints.

[joe90]

3 hours ago, MikeGrahamT21 said:

I have read it though I promise, BCO's look for the tape on the joints.

My BCO didn’t see any of the pipework or joints, just said on the final visit “you have no trickle vents because you have MVHR”. (didn’t even ask for the commission figures fir it). As the airflow is so slow is tape really required, virtually no air pressure I would have thought?

[MikeGrahamT21]

20 hours ago, joe90 said:

My BCO didn’t see any of the pipework or joints, just said on the final visit “you have no trickle vents because you have MVHR”. (didn’t even ask for the commission figures fir it). As the airflow is so slow is tape really required, virtually no air pressure I would have thought?

 

Yeah I'm not too sure either. Varies with BCO, some are really strict, and others just look for important bits.

 

Also depends on the kind of pipe used, i only used the tape on my 125mm plastic pipe joints, whether it sealed anything i've no idea, but I had some so thought i'd do it while i was up there.

[bluebirdnick]

On 27/01/2021 at 08:21, TonyT said:

It’s always easier to get a timber fixing on these, so it pays to install a plywood pad in the ceiling, just similar to putting plywood behind walls for radiators to get decent fixings.

Apologies for dragging up an old thread but I agree with this completely and indeed it is what I did above the old ceilings I was working with. But I've just seen a product call Ring Leader which looks like a neat and easy way to deal with this problem too (hence me dragging this up again). I still have one or two plenums to fit, and I'll be using these for it. 

 

On the subject of BCO: they send a different person along each time. The last guy didn't even comment on the MVHR; the one before that said he wanted to see the unit running but didn't have any concerns beyond that. 

[LeeV]

On 28/04/2020 at 20:35, JFDIY said:

I went and cherry picked components from a few places based on quality, cost or location (I.e. I could collect in person)

 

One thing I made extra effort to source was 150mm insulated ducting, I used the ubbink foam ducts as it looked easy to engineer the routes I wanted and no need to insulate separately after installation, can dismantle them for easy cleaning now installed as well.

 

 

There's some pics in this thread.

 

https://forum.buildhub.org.uk/topic/11747-silencer-can-it-be-mounted-horizontally/page/2/?tab=comments#comment-208334

 

Also made a few of my own vertical terminals for about £3 each, but mostly because I couldn't get exactly what I wanted

 

 

 

Sorry to revive an old thread but I have a quick question if I may?

 

Hi @JFDIY I've just come to the same conclusion that I need to make something, as spending £45 per supply/extract will cost more than the MVHR unit I've bought. I guess that is some ply for the base and 100mm rigid duct to connect to the ceiling vents, but what is that unit inside the duct? A 100mm to 90mm adapter maybe? Can I ask where you got them from?