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?

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.

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?

Thanks,

MC

On Jun 1, 10:17*pm, "MiamiCuse" wrote:
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?

The flex pipe is widely used for these applications because it's easy
to work with. That's what I would use.




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.

Tin snips.



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, the fan vent should have a direct exit. If it's just laid on top
of the soffit, as you pointed out, a considerable amount, maybe even
most of the air, is going to go back into the attic. Plus, the
soffit area is going to be cold, perfect for condensation to occur.
Probably much less of an issue in Maimi than northern climates, but
I'd still do it right. Plus, I would expect your code would require
it to be properly vented.





Thanks,

MC

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?

Thanks,

MC

It's one of those things that's not right, but its done all the time.
At least you pointed it out of a soffit. Most people just empty it
into the attic.
What I did is use rigid duct and ended it right by my attic fan on top
of the roof which is already open. At least it goes right up outside.
I really did not feel like putting a hole in my roof.

On Jun 1, 9:17*pm, "MiamiCuse" wrote:
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?

Flex saves a lot of hassles at the cost of slightly less efficiency.

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.

Sheet metal pros use double cut aviation snips. Wiss is a good brand.
If all you need to trim is an inch or so, then conventional aviation
snips are OK.

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.

Joe

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

On Jun 3, 9:42*am, wrote:

snip

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.

Your plan seems doable (excuse buzzword). Using a 4 1/4" hole saw on
the soffit would leave wiggle room enough for a length of pipe with
attached elbow to be threaded into the attic space. Pop rivets
attaching the elbow would be tidier and make installation easier. HTH

Joe

"Joe" wrote in message
...
On Jun 3, 9:42 am, wrote:

snip

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.

Your plan seems doable (excuse buzzword). Using a 4 1/4" hole saw on
the soffit would leave wiggle room enough for a length of pipe with
attached elbow to be threaded into the attic space. Pop rivets
attaching the elbow would be tidier and make installation easier. HTH

Joe

Yes it definitely help. I think still will be tricky on be on a ladder on
the outside (I already crawled from the attic on the inside and no luck
reaching that tight space) cut a hole and be able to cut the pipe back and
put in an elbow the same size as the hole and doing all that with one hand
inside the hole.

I will try to free the pipe from any straps and fasteners to the existing
joists...it will be tricky, and probably the solution to each of the four
bath will be different.

Thanks,

MC

"Joe" wrote in message
...
On Jun 1, 9:17 pm, "MiamiCuse" wrote:


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.

Sheet metal pros use double cut aviation snips. Wiss is a good brand.
If all you need to trim is an inch or so, then conventional aviation
snips are OK.

Thanks Joe. Is this one I can use:

http://www.northwaysmachinery.com/pr...%20Duct%20Snip

Thanks,

MC

On Jun 6, 10:42*am, "MiamiCuse" wrote:

snip
.

Thanks Joe. *Is this one I can use:

http://www.northwaysmachinery.com/pr...emNumber=Wiss%...

That's the one in my tool box. It helps to drill a 1/4" hole to start
the cut with the center blade. On soft thin aluminum the center blade
can sometimes be forced into the work to start the cut. Double cuts
must never be used for close trimming or edge cuts. Their special use
is on sheet metal with a good bit of material on both sides of the
outer blades. They are the only way to get clean cuts away from the
ends of vent pipe. Have fun.

Joe