Bugger! MVHR Inlet Issue

[worldwidewebs]

The MVHR and gas boiler will be located in the plant room, which is just under 1.9m wide. The plan was to put the gas flue and MVHR exhaust as far to one side of the room as possible (which is about 300mm in from the side due to joist positioning) and the MVHR inlet was to go above the room next to the plant room. That way I could easily get a minimum of 1.5m between inlet and exhaust.

 

Just looking at it now, I just don't see how I can possibly fit the inlet and I'm somewhere between stuck and really worried about it. Here's the problem...

 

The photo below shows the room I wanted to put the inlet above. There are a few issues:

• the insulated flexible duct and hence the duct to outside, is 180mm - this is 30mm more than what was in the original drawings from the supplier
• the gap between the upper and lower beams of the joists is 155mm - so can't pass the duct through it
• the gap between the wall and the nearest joist is 120mm - so not enough space to fit the flexible duct onto the duct to outside, even if I could get it through the joist

 

So what to do?

 

 

[dogman]

How about two smaller pipes side by side, with some sort of manifold 

[Declan52]

How about a pipe reducer like this 

http://www.jdpipes.co.uk/shop/store/product/324-170-192mm-x-110-125mm-drainage-adaptor/

Reduce the pipe then a short strip of 110mm to get you where you need to get to then another reducer to get you back to using the 180mm insulated pipe. 

You will obviously need to wrap something round this section. It would also reduce the inlet flow. By how much is beyond my maths knowledge.

Edited November 28, 2016 by Declan52

[ProDave]

Why can't it go through the wall of the plant room, i.e at ground floor level? Why does it have to go up through the joists to exit at first floor level?
 

[ToughButterCup]

Have I got this right.... the issue is the inlet, and the inlet alone?

 

Make a hole in the wall and insert the inlet ducting. Connect it to the the MVHR.

I expect I'm missing something here...

[Bitpipe]

You can get a combined inlet outlet - 

 

Or you could compromise on the separation distance - whats the max you can achieve in your plant room? You can consider angling the intake duct cowl away from the exhaust or have them at different heights to get your separation.

 

The idea to reduce the pipe diameter for a short distance is a good one also - do keep in mind though that when you wrap the duct in insulation you add about 20-30mm to the overall diameter.

 

Always a solution - I remember a few similarly 'impossible' scenarios with my MVHR that we managed to resolve.

[worldwidewebs]

10 hours ago, Bitpipe said:

Or you could compromise on the separation distance - whats the max you can achieve in your plant room? You can consider angling the intake duct cowl away from the exhaust or have them at different heights to get your separation.

 

You could do this for a living

 

The max separation distance I can get is just over 1m (or a bit more if the inlet is slightly lower down). I had a chat with BPC about this and they've said it'll be fine - and that I should angle the inlet cowl away from the exhaust! So, panic over  

 

[ProDave]

You mentioned a boiler flue. THAT would concern me more, achieving a proper separation between that and the mvhr vents. What does building regs say about that?
 

[worldwidewebs]

2 hours ago, ProDave said:

You mentioned a boiler flue. THAT would concern me more, achieving a proper separation between that and the mvhr vents. What does building regs say about that?
 

Nothing

[PeterW]

35 minutes ago, worldwidewebs said:

Nothing

 

If you read note 1 in the regs for Diagram 34 an opening is also a fixed vent so A B and C are applicable in this instance.