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CoconutPete 01-25-2012 10:09 AM

Booster fan on exhaust hood in kitchen?
Well ... one thing about tearing into old houses - there's always surprises :thumbup:

Long story short... because of the unique way the pipes are, I'm not going to be able to vent my hood to the outside the way I originally wanted. This is going to be a combination microwave / exhaust fan by the way.

The duct will need to come up from the microwave and turn right, run 3' to the right and then make a more or less 90 degree turn. The duct will then need to run just short of 12' to the outside wall.

Because of the 12' run I'm thinking I might need a booster fan. Is there a rule of thumb that I can use to find out if I actually need one? Number of 90 degree turns? Feet length of duct line?

jklingel 01-26-2012 01:12 AM

Coco: See what the instructions or manufacturer says. That always depends on the horsepower of the motor and size of pipe. You may already have a "booster" motor, in effect. BTW: When will the burgers be done?

CoconutPete 02-02-2012 02:05 PM

Burgers! We've been living off Microwaved frozen stuff my wife cooked before we tore the kitchen out haha.

Started working on hanging the microwave last night but decided to suspend those plans in favor of getting the sink working so we actually have a barebones kitchen again.

Still didn't see anything in the documentation about length of ductline, just a LOT about taking the blower out of the microwave and facing it a certain way depending on how you are venting it.

astersia 02-05-2012 03:52 PM

Why not disable the motor in the microwave and use an inline or exterior mounted fan with higher cfm's to account for the longer run?
I guess this is a "booster" fan, in a sense, but just replaces the inside motor completely. Outside mounts are much quieter, too.
Maximize the diameter of the duct.

Perhaps this is what you're thinking of:

I've not used this, but do have an exterior mounted Broan unit, many years old.

abracaboom 02-05-2012 06:13 PM

I think you're over-thinking this, Coconut Pete.

CoconutPete 02-06-2012 02:57 PM

I like the idea of the exterior mounted unit, takes some variables out such as accessing the hidden unit etc. I will look into that one - thanks.

abracaboom - why do you think I'm overthinking it? Do you think my run is not long enough to worry about a secondary fan?

beenthere 02-06-2012 04:24 PM

Doubt you'll need a booster fan. Is there a rating such as X CFM @ X static pressure?

CoconutPete 02-07-2012 09:12 AM

Not sure. Will check paperwork tonight.

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