Some pics of my first fix BPC/Vent Axia first fix install

[Cambs]

I’ve just spent most of last week installing the distribution boxes, ducting and plenums on my BPC/Vent Axia system.  I thought it would be worthwhile sharing some pictures,  It went well and was relatively easy to do.  I tried to keep ducting passing over each other in the joists to a minimum but it was unavoidable in some places.  Having two ducts on top of each other in a web joist was a bit tight and didn’t leave a lot of room for insulation.

 

I had already installed the 150mm PVC pipe through the roof and drilled a 150mm hole for  the second PVC pipe through the wall.  I then mounted the Vent Axia unit on the wall and figured out where to mount the distribution boxes in the metal web joists between the ground and first floors.  We have vaulted ceilings upstairs so it seemed easiest to mount the boxes here rather than up high in the first floor.

Here’s my rough in of the MVHR unit.  Ignore the angles of the pipes.  These will be straightened up on the final fix.

 

Here are the distribution boxes.  Required careful planning and it didn’t seem to matter where they were because of the metal web joists there was always at least one duct which was a tight squeeze through the joists.

 

 

I have a change in levels between the main part of the house and the lower level which causes a bit of head scratching as to how the get the ducts from one section to another.  This was exacerbated by the fact that there was a steel running across the lower level which I had to navigate around.  I built a dummy stud wall in the lower level and ran the ducts behind this.  I need to get 3 extract and 2 supply ducts into the lower level.  Here’s a photo after the first 4 ducts were run.  A bit of boxing in required to hide them, but relatively easy solution.

 

 

and here’s what it looks like in the lower level.

 

And finally, a ceiling mounted and wall mounted plenum.  I quite enjoyed doing it and it was satisfying to see it all done.

 

 

 

 

 

Edited May 4, 2020 by Cambs
Typo and delete duplicate photo.

[Savage87]

looking good! ?

[Andrew]

Install looks great. 

 

I spent a couple of hours yesterday trying to find an image of a plenum in a stud wall and today one shows up on build hub. Thanks for posting this, has really helped me visualise a couple of things. 

 

How did you find the wall mounted plenum - looks like a tight fit and you've had to put in a bit of hanging stud to fix it to? I'm also a bit concerned about drilling a 75mm hole in a 89mm stud but it seems to be the way it is done. 

 

 

What height are your posi-joists, they look like PS10 / 253mm?

[Jeremy Harris]

Looks good, but it might be very well worth fitting some short lengths of flexible duct from the MVHR to the rigid duct runs, to act as a vibration/noise absorber.  The vibration from the fan motors does tend to be easy to pass into the structure, so anything that can isolate that a bit is a good thing.

 

I installed our MVHR unit on soft rubber mounts for the same reason, to decouple the vibration from the house structure.

[ToughButterCup]

Thanks for your post.  A big help to me. I have an exactly similar problem to solve in terms of the levels. ?

[MikeGrahamT21]

Is that the quiet vent kit? I'm considering buying that, would love to know what you think about it. Seems to be a hell of a lot cheaper than all of the other manufacturers.

[Oz07]

16 hours ago, Andrew said:

you find the wall mounted plenum - looks like a tight fit and you've had to put in a bit of hanging stud to fix it to? I'm also a bit concerned about drilling a 75mm hole in a 89mm stud but it seems to be the way it is done. 

 

I think going through a noggin is a lot less important than going through a stud. Not sure i'd want a 75mm hole in 89mm CLS

[JFDIY]

You end up with about 1/4" either side if you're careful.

 

[MikeGrahamT21]

12 minutes ago, JFDIY said:

You end up with about 1/4" either side if you're careful.

 

And 3/4 of a screw! lol

[RandAbuild]

3 hours ago, MikeGrahamT21 said:

Is that the quiet vent kit? I'm considering buying that, would love to know what you think about it. Seems to be a hell of a lot cheaper than all of the other manufacturers.

We fitted one of the BPC silencers in our system. Not sure what difference it makes - the Vent Axia is pretty quiet anyway and radial ductwork avoids any cross-talk. But for the samll cost, I think it's worth fitting

[Cambs]

20 hours ago, Andrew said:

Install looks great. 

 

I spent a couple of hours yesterday trying to find an image of a plenum in a stud wall and today one shows up on build hub. Thanks for posting this, has really helped me visualise a couple of things. 

 

How did you find the wall mounted plenum - looks like a tight fit and you've had to put in a bit of hanging stud to fix it to? I'm also a bit concerned about drilling a 75mm hole in a 89mm stud but it seems to be the way it is done. 

 

 

What height are your posi-joists, they look like PS10 / 253mm?

Thanks for that.  
 

The plenum is a tight fit for wall mounting.  I took a length of 89mm deep timber to use as a noggin and had to cut a little notch out of it at the front to seat the little lug on the plenum in to. Drilling through the 89mm stud was ok.  It’s all nailed down to the floor anyway.
 

The posi-joists are 253mm deep.

[Cambs]

19 hours ago, Jeremy Harris said:

Looks good, but it might be very well worth fitting some short lengths of flexible duct from the MVHR to the rigid duct runs, to act as a vibration/noise absorber.  The vibration from the fan motors does tend to be easy to pass into the structure, so anything that can isolate that a bit is a good thing.

 

I installed our MVHR unit on soft rubber mounts for the same reason, to decouple the vibration from the house structure.

I will be fitting a length of flexible ducting.  That’s why the 150mm pvc pipe shown in the pics is currently running at an angle because I haven’t installed the piece of flexible ducting between the end of the pipe and the MVHR spigot.  I need to avoid it being crushed so the plan is, on the final fix, to hang the incoming PVC pipe from the timber frame to stop it crushing the flexible ducting.

 

That’s a good reminder about rubber mounts.  I seem to recall that you used bushings from a Mini or something similar?

[Jeremy Harris]

Just now, Cambs said:

I will be fitting a length of flexible ducting.  That’s why the 150mm pvc pipe shown in the pics is currently running at an angle because I haven’t installed the piece of flexible ducting between the end of the pipe and the MVHR spigot.  I need to avoid it being crushed so the plan is, on the final fix, to hang the incoming PVC pipe from the timber frame to stop it crushing the flexible ducting.

 

That’s a good reminder about rubber mounts.  I seem to recall that you used bushings from a Mini or something similar?

 

 

Yes, the mounts I used were Mini rubber exhaust mounts, fitted upside down:

 

[PeterW]

3 minutes ago, Jeremy Harris said:

 

 

Yes, the mounts I used were Mini rubber exhaust mounts, fitted upside down:

 

 

 

Yep I use them too...! £1.50 from Halfords from memory

[phatboy]

I have the same unit, and did find it to be a little noisy!

 

I installed the same ducting kit from BPC and no complaints.  I added a silencer on the extract side too, and since then it's very quiet in the house.

 

Since I did mine, they seem to have cheaper 75mm pipes - mine are all red, but green and blue are cheaper, and I cannot really see why!

[Jeremy Harris]

I found that I needed silencers on both the fresh air supply and extract, too.  The one on the extract side made a really big difference to the boost noise level in the utility room and downstairs WC, probably as both are pretty short duct runs.

 

I also noticed a difference in the price between the different colours.  Originally I was planning to colour code the extract and supply ducts, but the blue duct was a fair bit cheaper than the red duct, so they're all blue.

[MikeGrahamT21]

I'm not so sure they all have anti-bacterial and anti-static coatings on the pipe, don't quote me on that tho

[phatboy]

1 hour ago, MikeGrahamT21 said:

I'm not so sure they all have anti-bacterial and anti-static coatings on the pipe, don't quote me on that tho

 

The blue Domus seems to be the same spec as the red Airflex, and £30 cheaper.  The other ones nothing much is mentioned.

[Savage87]

I have used Blauberg and Airflex in my house and the later is a lot more bendable, both are anti static and anticacterial. So if it awkward to install, I would defitinetely go for Airflex.