Thread: Inline bath fan configuration

Came across this on yesterday's inspection, 2005 construction. One Fantech FR100 series inline fan is connected to all three bathroom exhaust vents. Two upstairs and one on main floor. The fan is wired to run constantly and is very loud, too loud IMO. There are no electrical switches at any of the bathrooms controlling this fan. The inline fan exhausts into the small furnace room about a foot from the waterheater. The mechanical room is located off the garage. This room has one small vent to outdoor air. My concerns are these:

• Shouldn't fan discharge be vented to outside air?
• Is 100 CFM enough air flow to be spread out over three bathrooms?
• Should the fan be controlled by an electrical switch at each bathroom?
• Is this an acceptable configuration?

I haven't seen this set up before. Any thought are appreciated.

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Originally Posted by Eric Williams

Came across this on yesterday's inspection, 2005 construction. One Fantech FR100 series inline fan is connected to all three bathroom exhaust vents. Two upstairs and one on main floor. The fan is wired to run constantly and is very loud, too loud IMO. There are no electrical switches at any of the bathrooms controlling this fan. The inline fan exhausts into the small furnace room about a foot from the waterheater. The mechanical room is located off the garage. This room has one small vent to outdoor air. My concerns are these:

• Shouldn't fan discharge be vented to outside air?
• Is 100 CFM enough air flow to be spread out over three bathrooms?
• Should the fan be controlled by an electrical switch at each bathroom?
• Is this an acceptable configuration?

I haven't seen this set up before. Any thought are appreciated.

This is the type of fan the is used in radon systems. They are great fans but they do make a little noise. They can also be used for venting inside homes.

• It needs to discharge to the exterior of the home.
• The 100 CFM is on the very very low range. I'm not sure, but I think the 100 is for 1-2 bathrooms. You need to check the Fantech website or call them.
• This controls should be in every bathroom if you want to control it from those bathrooms. I do not know of a specific requirement that each bathroom must control it.
• The setup is wrong as well as the way the fan is installed.

Take a look at the Fantech FR install guide it should help.
http://fantech.net/docs-resi/401444-fr-install.pdf

1) Needs to discharge to outside.

2) Per Fantech, needs to be a higher capacity fan , See note 1 under "Bath Ventilation" at this FAQ. Note also the requirement for a makeup air source.

3) Fantech recommends that when condensation is possible and FR series fan units and attached ducting are installed horizontally, that they be insulated and/or provided with a drain system (it's not all in the FAQ above, some of that it in tech-note somewhere on their site). I saw a horizontal installation with insulated duct (but not at the fan) where the fan housing filled with water (in crawl space), called Fantech and they said to drill a drain hole at the low point of the housing(!)

4) The fans themselves are OK for continuous run (see that same FAQ), the switching is a separate issue.

5) I don't know of a requirement at bath ventilation be switched at the bathroom, and I do not know if a disconnect method is required at the fan.

Scott,

Thanks for the reply. I do radon testing so I am familiar with this type of fan. There must be something stuck in the blades of this one. You can hear it from inside the house.

Originally Posted by Eric Williams

Scott,

Thanks for the reply. I do radon testing so I am familiar with this type of fan. There must be something stuck in the blades of this one. You can hear it from inside the house.

Most likely due to the way it is mounted. Aren't they really designed for vertical operation and not horizontal.

Is this somebody's bright (not) idea for providing combustion/make-up air for that poorly ventilated furnace closet?

Originally Posted by Scott Patterson

Most likely due to the way it is mounted. Aren't they really designed for vertical operation and not horizontal.

Here is what Fantech FAQ says about horizontal installs:

"Can the fan be mounted horizontally?
Yes, the orientation of the fan will not affect its operation. When running horizontal duct to the outside it is advisable to slightly slope the duct down to the outside vent (this allows condensation (if any) to naturally run out of the duct).

cation is acceptable"

Eric;

If that is only one step up into the room, AND the room does not have a door to the house, then the furnace is not mounted high enough off the garage floor...

Originally Posted by Darren Miller

Eric;

If that is only one step up into the room, AND the room does not have a door to the house, then the furnace is not mounted high enough off the garage floor...

Darren,

It was one step.. A 14" step.

Other being a dumb idea, look at the flex vent going into the fan. Does it looked collapsed to you? Flexible duct is intended for low pressure use not a vacuum. The installation needs metal duct on the input side of the fan.

Fans are a lot of them that are available in market. You may ask for a variety of them they would cost you a bit more but they would be bit costly.