Multi-port remote bathroom exhaust fan

[Ira]

Time to make a decision on how I want to vent 2-1/2 bathrooms. One full bathroom and the half bathroom are on the first floor, side by side, and the other full bathroom is above them on the second floor. I'm trying to keep roof penetrations to a minimum, so thinking about venting thru the nearby gable end.
 
Fantech has a remote fan with four 4" intake ports and one 6" exhaust remote fan that seems interesting. I would only have one 6" diameter gable end penetration instead of three 4" ones, so it would look better. Anyone have any experience with these or remote fans where the intake ducts have been Y'ed down to a single duct? Any concerns with the idea that when the fan is on, it is pulling from all three rooms, regardless of whether or not it needs to? How did you wire the controls from the three rooms?
 
Thanks,
Ira

 

[wkearney99]

I have a Fantech unit pulling from two sources, but they're in the same bathroom.  One is in a toilet 'water closet' and the other intake is in the large walk-in shower.  I can see good noticeable pull when taking a hot shower.   The fan unit is in the attic and there's zero noise at the intake grates.  Same thing with all the other bathroom fans, they're ducted to inline Fantech units.  

Note with new construction you may need to have a source of make-up air integrated with the fans.  Modern houses can be tight enough that exhaust fans can start pulling air away from other places like gas water heater, dryer, furnace or other sources of combustible air.  A make up unit will vent in outside air (usually through a heat-exchanger) to avoid that happening.

I only raise this point because you're looking to vent multiple units and that may draw a greater amount than expected.

I'd call Fantech and talk with them about it.
 

 

[vc1234]

I have a setup similar to wkearny99's. When I bought the house, there had been two ordinary push fans, in the WC and the bathroom itself, sending exhaust air to a Y-ed outlet. The inspector noticed and told me about the code violation (you cannot push  the air to the same exhaust pipe).  So, I installed a Fantech pulling the air from the exhaust side of the Y.
 
As to the wiring, you can for example have a Caseta switch with as many Pico companions as necessary installed at each location you want to control your fan from.  I have some doubts about the reasonableness of pulling the air from multiple rooms whenever someone visits a WC, though, but other than that it should satisfy your desire of having only one roof hole.

 

[wkearney99]

With decent ducting you can make the vents exit on less-noticeable sides of the structure.  I have all of mine on the back side of a roof portion, least-visible from most sight-lines I'd care about.

I went with non-automated Lutron timers, as it's nice to have an on-wall control over the time the circuit would be running.  I could have used an 8ANS switch, and accessory switches (3-way add-ons) but it was simpler to not automate them.

And in the 7 years since I can't really say I miss not having automated them, save for one powder room that sometimes gets double-tapped and thus set to on without timeout.  Not a biggie though, as it's a bathroom used fairly often.