I would appreciate any help with this problem. I’ve installed a 800 cfm range hood with 8″ duct to the outside. The end cap is like a giant dryer vent hood ,single flap under a canopy.The problem is that the wind rushes down a narrow passage between the two houses .The passage is about 3 feet wide then opens out to 10 feet wide about 5 feet before the vent. This causes the vent to flap very noisily.Has anyone found a solution to this by changing the air flow somehow?It is not possible for me to move the vent to any other position.I can certainly add sheet metal to the hood or change the hood,but don’t know what shape to modify the hood
thanks Jako
Replies
they make a dryer vent hood that may work. comes out wall in a "J", has a cap over the vent that outgoing air raises. I got mine at local hardware store.
First, it is possible to move the wall cap. As long as you have access, you can move it just about anywhere, within reason.
Some options to consider: replace the cap with one that has only a screen (Broan Model EH6, for instance) at the outlet and put a backdraft damper somewhere else in the system, like at the discharge of the fan (there may already be one there); or rotate the existing cap slightly such that the opening is exposed to the prevaling wind.
Hi Tim
Thanks for the response.Just to give you some more information ,the duct work is now impossible to access as it is in the ceiling behind a drywall ceiling ,behind a bulkhead above the upper cabinets.It runs vertically through the upper cabinets into the bulkhead about 3' then horizontally for about 7' and out through a double brick wall exiting 10' above ground.So the only changes I can make are at the outer end.bearing in mind that the duct is eight inch spiral duct. The blower is a " Best by Broan"rated at 800 cfm and has a very light weight aluminum flap on the top of the blower.I will certainly try your suggestion of rotating the cap and should anything else occur to you please let me know as the neighbors are getting all torqued up over the noise