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I am starting to design my MVHR system and will use the radial system. I am finding some of the components quite pricey ( manifolds) I know they have o rings and clips but I do wonder if these can be home made?. Jeremy made his own silencers and I wonder how difficult a manifold could be. I also like being able to adjust the flow at the manifold rather than at the terminal to keep noise to a minimum at the terminal. Can anyone point me at other suppliers that are reasonably priced? Any other info on DIY MVHR gratefully received.

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Way to go Mike, at £2.40 each that's £1.20 per connection ( plus a bit of mdf leftover from making something else.)  just need to work out how to restrict the flow at the manifold. ( Jeremy talked about knockouts but I have not seen them for sale).

 

There seems to be a big difference in price for what looks like similar pipe, the airflex is over twice the price of BPC,S quietvent pipe of the same size!!!

 

Is there any need for both silencers and manifolds, can't a manifold be a little larger and contain sound absorbing foam?, saves making more mdf boxes and more pipe connections?

 

Next is the plenum and terminals, at £24 ish each and I need 9.

 

my motto has always been " why buy something when you can make it?" ( and that includes a house ?)

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6 hours ago, joe90 said:

my motto has always been " why buy something when you can make it?" ( and that includes a house ?)

 

Does that extend to making the heat exchanger in the MVHR? :)

 

Half serious question that, when I read the thread title I actually thought that's what you were up to.....and something I've wondered about myself.

 

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3 hours ago, Onoff said:

 

Does that extend to making the heat exchanger in the MVHR? :)

 

Half serious question that, when I read the thread title I actually thought that's what you were up to.....and something I've wondered about myself.

 

No, I managed to get a unit from EBay for a few hundred quid, ex kingspan. It's just that I started adding up the cost of all the bits to instal it ?

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I can't see any reason why the silencer and manifold can't be the same box, if you can make room for a combined unit.  One of my home-made silencers (the one that's almost hidden from view) is an MDF box sat directly on to the 150mm stub that comes out of the manifold.

 

The flow adjustment discs fit to the HB+ manifold connections, and are secured in place by the quarter turn locking ring, so it would be challenging to get them to fit. 

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12 hours ago, joe90 said:

( Jeremy talked about knockouts but I have not seen them for sale).

 

I bought a load of these then found they wouldn't fit on my manifolds, I think they are in the shed somewhere.

 

I'll look them out and if I find them I'll post them to you for free, rather they get used than go in bin

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On 10/03/2017 at 05:14, Onoff said:

Does that extend to making the heat exchanger in the MVHR?

 

Half serious question that, when I read the thread title I actually thought that's what you were up to.....and something I've wondered about myself.

I made mine.  Still up in the loft working away.

I also have some other ideas on how to make it easier and cheaper.

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46 minutes ago, SteamyTea said:

I made mine.  Still up in the loft working away.

I also have some other ideas on how to make it easier and cheaper.

 

You made the heat exchanger, from scratch? Did you cannibalise something else?

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From scratch.

Was not that hard, i wrote up about it over at the other place. 

Probably time to make a Mk3 version with better fans and a cheaper to make exchanger. And add some logging gear to it.

Having a bit of a complicated week or two at the moment, but should be back to normal soon. Then can get working on some ideas.  Maybe the electronic boys can think up a simple fan controller that can be used from a Raspberry Pi. I have some thoughts on that too.

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1 hour ago, SteamyTea said:

From scratch.

Was not that hard, i wrote up about it over at the other place. 

Probably time to make a Mk3 version with better fans and a cheaper to make exchanger. And add some logging gear to it.

Having a bit of a complicated week or two at the moment, but should be back to normal soon. Then can get working on some ideas.  Maybe the electronic boys can think up a simple fan controller that can be used from a Raspberry Pi. I have some thoughts on that too.

 

Any idea of the efficiency of your design?

 

I can possibly get working but scrap fan coil units on a regular 'ish basis. They get binned but it's usually just the bearings. Wonder if they could be put to use?

 

Wonder though if there's any point in my "air leaky as a sieve" place! :)

 

 

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On 12/03/2017 at 18:27, Onoff said:

Any idea of the efficiency of your design?

At its best, I seem to remember, that it was 75%.

It is only a replacement for the bathroom fan, so worked intermittently which plays havoc with efficiency numbers.

I never got around to testing it properly, but from the data I did collect, there was some interesting numbers when the thing turned off and moisture condensed (well over 100% efficiency [CoP]).

 

Still not had time to jot down my thoughts on a new design, but will try to soon.

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  • 1 month later...

raising this thread again as I am about to order my MVHR duct and bits, BPC quiet vent duct appear the cheapest, I am going to make my own silencer and manifold. The plenum and valves are expensive , I can get metal ceiling valves at £3.60 each ( I don't need the adjustable ones as I plan to balance the system at the manifold, and pipe reducers about a couple of quid and don't need a 90' bend as the pipe will bend that much. If it works this will save in the region of £200. Am I just tight fisted ??????

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As long as you aren't in a tearing hurry, and postage isn't too much, order the minimum you can get away with and then do a follow-up order once you've started installing and can see exactly what you need.


Tight fisted is good.  I reckon we wasted £200+ on bits and pieces we didn't need.  I can't even give them away, as it's a bit of an unusual duct format.

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How much do you value your time at? And do you have time to spare? The stuff from BPC turns up and you can get started right away. As much as I like a saving I've got to balance it with the extra time which we don't have any to spare really. That said,  I'll argue with Jewson over an extra £30 but that's out of principle rather than being tight per se.    

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Due to uncertainty over the manifold position, I over ordered on flexible and steel duct. Ended up using almost all of the 350m of flex and have about 6 x 2m lengths of steel 180mm duct, plus insulated flexible duct of the same size and a roll of foil backed insulation.

 

Not entirely sure what to do with it - doesn't seem to come up on eBay or Gumtree much and the postage makes it impractical to return or sell outside of collection.

 

Maybe I'll just strap it to the side of the house in a homage to the Pompidou Centre / Lloyds building.

 

 

 

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26 minutes ago, Bitpipe said:

Due to uncertainty over the manifold position, I over ordered on flexible and steel duct. Ended up using almost all of the 350m of flex and have about 6 x 2m lengths of steel 180mm duct, plus insulated flexible duct of the same size and a roll of foil backed insulation.

 

Not entirely sure what to do with it - doesn't seem to come up on eBay or Gumtree much and the postage makes it impractical to return or sell outside of collection.

 

Maybe I'll just strap it to the side of the house in a homage to the Pompidou Centre / Lloyds building.

 

 

 

I'm the exact same! Seems a waste but BPC prefer to send out a bit more. 

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Thanks guys, yes I do have a lot to do but I am retired so I don't have to balance site with a job. The only thing I don't like about the BPC type plenums is they are fixed before plasterboarding so fitting the boards around the pipe sticking out from the ceiling could be a fag, I would prefer to have a flexible connection above the plasterboard and cut up into it after the plasterboard was fixed.

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17 minutes ago, joe90 said:

Thanks guys, yes I do have a lot to do but I am retired so I don't have to balance site with a job. The only thing I don't like about the BPC type plenums is they are fixed before plasterboarding so fitting the boards around the pipe sticking out from the ceiling could be a fag, I would prefer to have a flexible connection above the plasterboard and cut up into it after the plasterboard was fixed.

 

We fitted them before plastering and I trimmed them with a multitool after skimming. Probably should have trimmed after boarding and before skimming to enable the plasterer to get a perfectly neat finish. 

 

Anyway, it really doesn't matter as the ceiling fitting overlaps by a good inch or so and covers up any imperfections. 

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I laid all the ductwork and positioned the individual plenums prior to plasterboarding.  The joiners sheeted the ceilings then I simply cut out the holes for the plenum to go through, cutting each plenum to the correct length for a flush finish.  The only plenums that the joiners fitted the plasterboard around were those in the vaulted ceiling where there was no subsequent access available.  As they had to measure and pre-cut boards anyway, it wasn't much additional work to measure and cut out the hole for the plenum which I had previously cut down and fixed in place. 

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  • 3 weeks later...

In the process of ordering duct to discover BPC only do 50 meter RolIs and I need 75 ( Domus do 25 meter rolls but not half the price !). Anyone know where I can buy 25 meter rolls or has anyone got half a roll that I can buy from you ?. Does anyone know if Domus is the same as quiet vent from BPC ( so fits their joiners etc).

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If you end up with a half roll spare, I might need some.

 

My rough calculations showed I needed a total of 205 metres, so I have ordered 200 metres. So if I end up a bit short.......

 

75 metres does sound not very much. and I didn't think my house was very big.

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