Pre filter between MVHR vents and MVHR unit

[JohnMo]

47 minutes ago, Russdl said:

A sheet of PIR or similar fits the first 4 criteria but falls down on the last.

But does it fail if you add local reinforcements (metal or wood) in local stress areas. You can make strong corners by using dowels, and even screw in to dowels etc.

 

An idea here

 

[Nick Laslett]

Why not just buy some armaflex sheets and glue this to the exterior of the existing box? This is what I did with the galvanised steel filter box from Zehnder. 
 

Funnily enough just stepped out of my place, to be passed by farm vehicle moving manure. On Sunday, next door had a bonfire. 
 

So glad I’ve got a pre-filter for all these country smells. 

Edited July 22 by Nick Laslett

[Russdl]

@JohnMo thats interesting, thanks for the link.

@Nick Laslett that would prove difficult to get an airtight seal on the current boxes.

 

I was thinking I could do with something like a ply backed PIR - which of course I've now discovered does exist!

 

As I have a sheet of insulation left over from the garage build I think I'll experiment with the local reinforcement idea, or maybe make my own PIR backed plywood sections, or perhaps a combination of the two.

 

What would be the best way of adhering foil backed insulation to plywood?

[JohnMo]

7 minutes ago, Russdl said:

What would be the best way of adhering foil backed insulation to plywood?

Spray foam, allow to flash off and not stick fingers when touching and squish together (dampen surface first). Bit like foaming plasterboard to the wall.

 

Or you can use double sided tape, the decent scrim stuff used for sticking vapour membrane together.

[Mike]

3 hours ago, Russdl said:

To that end I'm going to be remaking them but what material should I use?

If you're willing to forego the DIY & the 90° bend, you may be able to buy them.

 

The Zehnder IsoBox, for example, is made from EPP, has a DN160 connection & can take a pre-filter, a carbon filter, or both. Or a DIY filter, I guess. Paul used to sell them in the UK.

 

I guess that other manufactures may make similar for larger ducts.

 

 

 

Edited July 22 by Mike

[Mike]

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Edited July 22 by Mike
double post

[Russdl]

Thanks @Mike, everything was originally built around replacing a 90° bend so that if I screwed it up I could remove my Heath Robinson filter and refit the 90° bend - so the 90° change of flow direction is one of the few certainties.

 

However, I could refit the original 90 and cut out a bit of the straight duct flow for one of those boxes you linked to. I've never seen those before but I suspect they don't give them away - or the filters? I'll take a look.

[SteamyTea]

On 07/08/2023 at 07:27, Russdl said:

Also the power draw 67W before 34W after. 

When I did my toolmaking apprenticeship, we combined machine amperage and an assigned tool life so we knew when to change the work bits.

Mayne you can do something similar, say 4 months and 50W.

[Mike]

3 hours ago, Russdl said:

Thanks @Mike, everything was originally built around replacing a 90° bend so that if I screwed it up I could remove my Heath Robinson filter and refit the 90° bend - so the 90° change of flow direction is one of the few certainties.

 

However, I could refit the original 90 and cut out a bit of the straight duct flow for one of those boxes you linked to.

A good idea :)

 

The best price I found was €85, carbon filter included, from https://www.econology.fr/zehnder-comfosystems-caisson-filtrant-isobox-dn-160-filtre-a-pollen.html, but there's not going to be as much competition in the UK market.

[Russdl]

As expected, they don’t give them away!
 

As I’ve got some bits and bobs lying around I’ll go with rebuild and if that fails reconsider the pro version.