# Kitchen Extractor ducting question



## Gixxer6 (Apr 5, 2014)

I hope that someone can help me with a question on ducting for an extractor fan that I am planning to buy. I'd like to connect the ducting to vent externally but the product manual mentions that the extractor has a 150/120 fitting (it's 150 with a reducer fitting to 120). I have seen that you can buy PVC pipes that are 120mm diameter but I'm struggling to find a 120mm ducting kit. The 125mm size seems to be more popular so I was thinking that I could buy a 150 to 125mm reducer and then fit a 125mm kit to that. Would that be a good idea or should I buy separate 120mm parts and assemble my own kit?
Where would be the best place to buy a ducting kit or parts for the extractor?
I've found the following site through a search: https://www.tlc-direct.co.uk/Main_Index/Ventilation_Index/Ducting_1/
the wall grilles (with back daft shutter) are listed as 5 inches which is 127mm, would these grilles be able to accommodate a 120mm pipe? I'm guessing that the 120mm pipe will fit into the 5" grille, but would it be a good fit or a loose fit?

Thanks!


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## rf860 (Jul 24, 2011)

I'd save yourself the bother and buy an extractor that doesn't need ducting (most have this option).

If you really want ducting, the 125mm one will be fine just use a couple of cable ties to hold the ducting onto the fans outlet and also duct tape the joint to seal it.


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## WHIZZER (Oct 25, 2005)

My extractor is fitted to 5" and has the grill ( draft shutter) and I believe my extractor is fitted with Flexi pipe to the external wall fitting










See search

http://www.ebay.co.uk/sch/i.html?_nkw=kitchen+extractor+kit


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## REVERSiN (Sep 28, 2015)

You can do that as you wont go less than 120mm as the ducting provides you. Any pvc pipe as 120 can fit a 125 if heated and press 5mm isnt too large and can still expand freely this is a solution idlf you are looking to do this on your own. Anyway its a ducting so no real pressure will be held it wont fly off if you suspect that.

Or if its goving you a hard time as suggested replace it buy another.


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## Deniance (Jun 28, 2008)

Try and avoid the flappy ones!, in high winds they make hell of a flappy sound, you have been warned!


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## Gixxer6 (Apr 5, 2014)

Thanks for the replies everyone.

Yeah the flappy one's I've read about, I have the cowl style one installed for the bathroom and that one also flaps in the wind: Air Vent Grill Cover Gravity Flap(Ducting 125mm)Brown External Ventilation Cover: Amazon.co.uk: DIY & Tools

I've read that it's better to get the solid PVC pipes instead of the expandable pipes as fat and dirt can be trapped in the ridges.
I'd rather be researching detailing products!


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## Deniance (Jun 28, 2008)

If you research enough, you will find that there is a lot of talk about air tightness in homes, and extractor ducting is basically a 125mm hole in your house for heat and air to escape, apparently the detailing world of the green building forum compares this dirty practice with using a water blade to dry your car, they suggest using insulated ducting, a million times sealed and a 125mm electric blanking valve in line with the ducting that opens when you turn on extractor and closes when off, stopping air and heat leakage, also flexible ducting is frowned upon


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## Gixxer6 (Apr 5, 2014)

Lol Deniance that's exactly what I need! 
I was reading about the electric valve, no more flapping in the wind and even stainless steel external valves which can probably be detailed, polished and waxed ... hmmmm extraction is becoming more interesting


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## G.P (Dec 13, 2011)

If you use Vent-Axia, all there parts will slip inside one another as they provide duct and flexible duct to suit their fan range spigots.

They used to have an auto mechanical shutter linked to the impellor shaft..


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