We are considering fitting air conditioning to our MBC build and I’m just working out how best to get the pipework fitted if we do go down this route. It’s looking like the best way is to fit a conduit, make it air-tight around its perimeter with an air tight grommet, push the copper pipe complete with its insulated sleeve through the conduit and then squirt some low expanding foam (or something similar) into the conduit just to improve the seal between the conduit and the pipe insulation.

 

As an approach, how does that sound? And is the low expanding foam idea a good one or not?

 

TIA

Don't use foam ....

 

Most refrigeration pipes use 10mm copper with a measly 9mm Armaflex or Insultube on them. Upgrade the insulation to a 28mm bore 25mm wall over layer of tuffcoat if you can get it as it's UV stable and use this to "seal" your hole through the wall, sleeving it through a 63mm down pipe. 

 

The insulation will compress enough for you to push it into the ducting and it lets you replace the outer layer if it degrades or gets damaged. 

 

Thanks Peter. To confirm, are you suggesting that if the copper pipe is 10mm then it should go through a 63mm pipe/conduit? I was hoping to keep the holes as small as possible as, depending on how many indoor units we have, we may need 6-8 pipes in total.

 

Ideally I wouldn't fit the air con, but we have a lot of glazing and the risk of the house getting warm is there, despite the PHPP calculations suggesting otherwise. It's far easier and cheaper to do it now than after the event!

Anything smaller would need sleeving anyway - refrigeration pipe is 10mm soft copper normally, which gives you 28mm OD with insulation. You could go for 10x15 which would compress into 32mm waste pipe but that's about as small as you would want to go. 

 

If you are planning now then get a refrigeration engineer to have a look - with proper design you could end up with just a single external unit for 2 or 3 internal units, saving on pipe work, wiring and holes !

Thanks Peter. Yes, speaking with people at the moment but the indoor units we like (Mitsubishi Zen) don't work off a branch box so either we'd have to have more pipework or different (even more ugly!) indoor units.

 

I'm starting to look at window films now too!

Why not go for a ducted unit ..? It would be less obtrusive but would make a mess of balancing mvhr..!

What's the purpose of the air conditioning?