On Jun 3, 7:37 am, "Joseph Meehan" wrote:
I don't see the response I wrote to this question so here it is again,
along with some additional comments.

"MiamiCuse" wrote in message

...

I am installing two Panasonic bath exhaust fans - one FV-08VQ3 and one
FV-11VQ3.

Because of the difference in size and location of the new fan, I have to
extend the existing 4" sheet metal conduit to the new fan. They are about
30" apart. Should I use new sheet metal conduit to bridge this 30" or
should I use a "coiled" looking flex conduit? or PVC pipes?

When possible use the solid. The flex stuff will reduce air flow. It
is harder to install sometimes, but better once in place.



I need to cut the existing sheet metal pipe back a bit, what is the best
way to do this? The attic space is tight I am pretty much limited to hand
tools.

See the other Joe's answer, it is 100% correct.



Also, I traced the conduit and found that all the bath exhaust conduit do
not exit the roof, but simply extended to the roof overhang and sat on top
of soffit openings. Is that ok? When the fan is on and moist air is
drawn, part of it will exit the soffit vent, but part of it will go inside
the attic. Is this acceptable?

NO NO NO! It is often done that way, but it is a very very bad idea.
To protect your home you want to get that warm moist air out of it not just
move it into the attic where it may cause bigger problems.


well I have four bathrooms that are "vented" this way via the soffit.
I don't want to punch 4 holes in my roof.

One possible solution would be to cut a 4" hole in my soffit overhand
(I have a 5' eave overhang all the way around the house with T-111
plywood soffit), so I cut 4" holes in the T-111, then terminate the
exhaust pipe with a 90" elbow (somehow) facing down and exit via the
soffit. No air will go back into the attic but the moist air will be
forced downward. I assume I need some lip/cover to prevent backflow
or critters from getting into it.

But since my 4" lines are all currently directing to a soffit vent, if
I cut a 4" hole, I need to cut it along the current path and then cut
it short to install the elbow. I wonder if I realistically can cut
and install a 4" sheet metal pipe and put in a 4" elbow from outside a
4" hole...seems it would be tricky. I don't think there would be a
problem were it sheetrock but it's T-111 ply.

This seems to be the only possible solution I can think of now that
does not involve a very expensive and intrusive remedy. Any other
thoughts would be greatly appreciated.



Thanks,

MC

--
Joseph Meehan

Dia 's Muire duit