6 to 4 inch duct flange

[Nookies]

There it is, basically I don't want to drill a massive 6 inch hole into the wall if I don't have to. I'm wanting to do a 4 inch hole, then use a 6 to 4 inch duct reducer.

However there is a couple concerns.

Will it reduce airflow?
Will it stress the inline fan in any way?

Thanks <3

 

[ScoobyDoobyDoo]

as long as you pull the air through the reducer and not try and push it then you should be ok. if you are using a 4" fan and pulling the air then you won't have any reduction in airflow.

 

[Nookies]

Hmm, so if I understand you correctly in order to pull the air through I would actually have to have the inline fan on the opposite side of the wall hooked up to the flange itself with a very small srip of ducting?

I would no longer be able to just have the fan mounted within the same closet.

So NOT Ducting >> Fan >>> Flange

But rather Ducting >>> Flange >> Fan

 

[AimAim]

Will it reduce airflow?

Well I assume you have a 6" fan or you wouldn't have 6" ducting. If that's the case you are restricting airflow.

Hell if you're knocking holes in the wall knock a nice big one.

 

[brimck325]

i wonder if it would be ok if he used a speed controller at 1/2 speed to push the (i'm assuming) 6" fan through a 4" flange.

 

[ScoobyDoobyDoo]

my understanding is that pushing air through ducting, flanges, hoods, etc... makes for positive air pressure in you line and therefore reduces the life of your fan by creating drag on the motor. fans are designed to pull air so you want as little behind it as possible. will it make a difference in your lifetime on one fan...probably not.

 

[colonuggs]

if your fan has good cfm and is deigned to use a 6 inch exhaust pipe and you reduce to a 4 ....your also reducing the rate of your air flow

6 inch pipes carry more air than a 4 inch.... a higher rate of cfms pass through it

90* bends reduce flow too

setup the filtration ...fan to pull the smelly air through the filter..dont push it

 

[machead]

Cut a 6" hole no point having 4" hole with 6" fan.

 

[Nookies]

k, 6 inch hole it is. I'll be putting on a vent, on the other side so it doesn't look ghetto. Similar to a dryer vent one on the outside of your house. Now I just need to find a vent that doesn't stand out too much.

 

[machead]

yeah try get one same colour of your bricks or as close to it.