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Capra Aegagrus
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Can I couple the (2) 4" aluminum vents into 1 common 4" vent?
In theory that would work as long as both fans aren't running at the same time. Each fan will have a flapper to prevent reverse air flow. But if they're both running, neither one will be able to push the air at full efficiency. :no:

Related question: Where are you running the vents to? Roof vent, ridge vent, gable wall? The last is best when practical. And remember not to have any low spots in the run that could collect condensation. :thumbsup:
 

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I've always done separate runs. My thoughts on this are because that little plastic flapper on the fan units aren't very substantial and you dont want a deuce from one bathroom to be evident in adjacent bathrooms.

I would imagine that if there is any air pressure on them at all (from the wrong direction), they would open.

Just my $0,000.02
 

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I own stock in FotoMat!
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I'm a wierdo. Since I'm an electrician, I let the HVAC people do the venting.
 

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This is why the mechanical contractor should install the fart fans.
I agree for new construction or remodeling, but I must admit that for swap outs on service calls, I have run these myself. I usually duplicate the existing setup, unless they just vent into an attic.
 

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Service & Repairs
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Discussion Starter · #10 ·
A) Gable ends (split level home).
B) Because I'd rather not sub out any venting on a small job such as this.
C) Thanks for the link.
D) Chewing gum and walking at the same time is something I learned very early on in life.

I'm going to install 2 separate runs. Seems to make the most sense. There is a very good chance of both fans being on at the same time.
 

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Service & Repairs
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Discussion Starter · #11 ·
This is why the mechanical contractor should install the fart fans.
Hopefully I get this job I went looked at today. Complete gut job remodel. I will be more than happy to have an HVAC professional do the venting. :thumbsup:
 

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Mag - I've put a "y" connector right close to the exterior vent and then connected two runs into that. Kind of a last resort thing if they don't want two vents, etc.

Also, it's usually far enough down the run that backdrafting would not be a problem.

x2 with that Tin said about low spots. Also, think about insulated ducting if it is in an attic area.
 

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Discussion Starter · #16 ·
Mag - I've put a "y" connector right close to the exterior vent and then connected two runs into that. Kind of a last resort thing if they don't want two vents, etc.

Also, it's usually far enough down the run that backdrafting would not be a problem.

x2 with that Tin said about low spots. Also, think about insulated ducting if it is in an attic area.
I was planning on doing it like I've always done it.... flexible aluminum.

Is that bad (really bad!) because the moisture meets the cold in air in the winter?
 
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