Flexible conduit and filter box for ventilation system

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timmmay

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#146691 26-May-2014 13:17

I'm considering modifying my ventilation system to draw fresh air from outside rather than the ceiling cavity. The motor unit has a 220mm diameter, so I guess I need 250mm conduit. I found a place that will sell it to me for $90 + GST for 6 meter lengths, though of course I need 7 meters. Plumbing world is $50 for 3 meters. Both seem pretty expensive. I could probably get away with 200mm conduit, with some liberal use of duct tape.

They also sell filter boxes for $325 + GST. It's a metal box with connectors for conduit (150 or 200 mm I think) and a simple cloth filter inside. Can anyone point me at something cheaper?

stuzzo

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#1053578 26-May-2014 13:45

Small point but (despite it's name) don't use duct tape for ducting, use a foil tape.

shanes

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#1053589 26-May-2014 14:01

Are you in Wellington ?

http://www.ahi-carrier.co.nz/wellington-area/ have a lot better pricing than that...

itxtme

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#1053609 26-May-2014 14:27

Used electricalLtd a few times, dont know how much you would save with delivery, unless you are in Auckland and want to pick up!

ElectricalLtd Melrose ducting

timmmay

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#1053703 26-May-2014 16:37

stuzzo: Small point but (despite it's name) don't use duct tape for ducting, use a foil tape.

Even for cold air ducts? It looks like the old, cheap ventilation system used duct tape, it's survived fine for many years.

shanes:
Are you in Wellington ?

http://www.ahi-carrier.co.nz/wellington-area/ have a lot better pricing than that...

Yep, in Wellington. They have no prices online, do you happen to know or should I give them a call?

itxtme: Used electricalLtd a few times, dont know how much you would save with delivery, unless you are in Auckland and want to pick up!

ElectricalLtd Melrose ducting

Thanks, similar prices to plumbing world.

RGP

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#1053962 26-May-2014 21:58

Check out 200mm x 6m insulated ducting on Trademe - listing # 733860661. I'm looking as well and this is the best deal I've seen.

shanes

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#1054070 27-May-2014 08:30

timmmay:
shanes:
Are you in Wellington ?

http://www.ahi-carrier.co.nz/wellington-area/ have a lot better pricing than that...

Yep, in Wellington. They have no prices online, do you happen to know or should I give them a call?

Sorry I can't remember, but pricing was way better than anything on Trademe or the usual hardware stores.

Give them a call, I've just walked in off the street into their showroom a couple of times and I was surprised how helpful they were.

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timmmay

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#1054073 27-May-2014 08:36

That is a good deal. I don't need insulated ducting, and with shipping may cost more than locally unfortunately. Thanks for the suggestion though.

Fred99

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#1054123 27-May-2014 09:38

This article about fire risk with (one brand?) of heat transfer equipment is a bit of a concern.
I'm thinking of putting a heat transfer system in our place as part of post EQ interior repairs/renovations. It surprises me that motors could be used in such applications apparently without even simple klixon type thermal switches for overheat protection, and that flammable materials could be used in ducting.

timmmay

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#1054127 27-May-2014 09:45

I'm not transferring heat, just ambient temperature air.

timmmay

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#1054223 27-May-2014 11:27

Yep AHI do it, through their total line store

http://www.ahi-carrier.co.nz/parts-supplies/

For reference

200mm 3m $12.80 6m, $25.60
250mm 3m $16.30 6m, $30 ish

Thanks for the tip, definitely much cheaper than other places!

andrewNZ

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#1054267 27-May-2014 12:35

For filters, I used Green Sheep recently and was happy with the price and product.

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#1054289 27-May-2014 13:02

The way some of the PPV crowds do it is simply an induction fan under the eaves, which can force fresh air into the roof cavity in case the roof cavity air is hotter than you'd like. Might be an easier solution than ducting etc.

timmmay

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#1054308 27-May-2014 13:33

andrewNZ: For filters, I used Green Sheep recently and was happy with the price and product.

I need the whole enclosure, some way to put the filter inline in the conduit.

ubergeeknz: The way some of the PPV crowds do it is simply an induction fan under the eaves, which can force fresh air into the roof cavity in case the roof cavity air is hotter than you'd like. Might be an easier solution than ducting etc.

Given how dusty it is in my ceiling cavity I'm not sure it would help a lot in this situation. My main issue is the dust, cobwebs, and apparently old rodent faeces up there that's been collecting for 100 years, with bits of it going through the filter and being pushed down into the house. I was up there for two hours yesterday doing more insulation, I'm not going to go into any detail but I got a fair bit of the stuff into me and I did not feel well afterwards.

ubergeeknz

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#1054312 27-May-2014 13:35

Given how dusty it is in my ceiling cavity I'm not sure it would help a lot in this situation. My main issue is the dust, cobwebs, and apparently old rodent faeces up there that's been collecting for 100 years, with bits of it going through the filter and being pushed down into the house. I was up there for two hours yesterday doing more insulation, I'm not going to go into any detail but I got a fair bit of the stuff into me and I did not feel well afterwards.

Eww. Fair call.