Condensation Drips Down Exhaust Fan

[bobbopulaus]

I Have Water Coming Down Kitchen Exhaust Fan.it Is Vented Thru Roof And Not Insulated.its 10 Inch Diameter.would Insulating Solve My Problem.i Also Have The Same Problem With A Bathroom Fan.its Flexible Tubing.should It Be Rigid Tubing And Insulating.thanks Much

[kactuskid]

Yes, they both should be insulated to keep the moist air from condensing inside the ducting before reaching the outside. Also make sure the ducting is ran in the shortest and straightest run possible. This provides less resistance so the moisture can escape quicker. A ridgid exhaust duct is always the best way to go since it is smooth on the inside, thus less resistance to air flow. The metal flex can be used though as long as they're stretched out so the surface is smooth.

[bobbopulaus]

thanks kactuskid.the flexible tubing runs about 15 feet to gable.too long.will have to vent thru roof,about 5 foot run

[kactuskid]

You may be able to keep venting out the gable wall, but to do so and allow the air to escape quickly you'd want to install a 4" duct and have it sloped upwards towards the vent so the horizontal run isn't flat. Of course through the roof is better, just be sure to buy the special hooded vent for it. The attached link will show you a picture of it.

http://www.askthebuilder.com/546_Bat...tilation.shtml

[bobbopulaus]

hey thanks again kactuskid.my kitchen duct is about 10 diameter.its rigid tubing.it runs straight thru the roof.i 'll have to insulate it.do you think the tubing is too big?the roof ventopens about an inch or so.is that a normal opening during use?

[kactuskid]

I can't say if 10" is too large or not, the manufacturer is the one that sets the size so check the manual for the exhaust fan if you have it. It would also be a good idea to run the fan longer to allow it to rid all of the moisture along with insulating it.

A good thing to do is to install a timer in your bathroom in place of the fans toggle switch. You can buy an Intermatic 60 minute timer at Home Depot for around $15.00. This way the fan can run for 20 minutes or so AFTER you're done showering and you won't have to worry about shutting it off.

[bobbopulaus]

Thanks Again Kactuskid.didn't Even Think Of A Timer Swich.your Right,i'll Have To Check The Man.manual For Duct Size.

[vdotmatrix]

I am replacing the old noise box with a panasonic FV-11VHL2 . I have the option now to put in a broan RVK1a kit straight up through the roof or laterally to the soffit.

I keep thinking that if I vent straight up I'll have water condensing and dripping back down into the fan assembly-kaboom!!! or go latterally to the soffit and vent out to the side.

WHAT DO YOU GUYS THINK

[jnaas2]

Vents are sized according to the distance run and the elbows installed to get the size duct needed. The instalation manual will tell you what size pipe is needed for the run and elbows installed. I have installed a lot of vent pipes and never have I needed to install a 10 inch pipe. If the pipe is oversized it will allow the moisture to condense on the pipe and dripinside. What size is the pipe when it leaves the fan