Any issues using 4" ducting fan with 3" existing duct pipe
Our powder rooms' fan is 16 years old and loud (its the 696ND - says its 2.5 sones but it seems much louder!). I'd like to replace it with a modern quiet fan. The existing ducting is 3", and would be difficult to change as the room is in the middle of the house.
Most of the new quiet fans (< 1.5 sones) have 4" venting.
Is there any issue using a duct reducer (4" to 3") with these fans?
FYI, It a small powder room (< 50 sq ft).
What happens is your static pressure will increase (friction in the pipe) causing your 80 CFM fan to run at about 75 to 78CFM. All depends on the length of 3" pipe. The smaller pipe also increases the speed on how fast the air will travel down the pipe. Being a 80 CFM unit, shouldn't be a problem, but anything larger I would suggest going to a 4" to keep the noise down.
Date published: 2013-10-23
how do i remove grille ?
i tried pulling grille down. but it would not come lose. afraid if I used more force something might break. fan is 1 year old. please advise.
Just pull down from the ceiling. The spring action is very strong and adheres well, don't be concerned about damaging anything the unit is very strong.
Date published: 2014-05-17
the unit seems to be running but is not pulling out any air...
unit runs very quietly and will not pull any air from the room. you can see the unit spinning......but no air pull.
Thank you for your question on the model QTR080 exhaust fan. If the fan is turning but not removing air, check to make sure the back draft damper is opening when the fan is turned on. Next you would need to check the duct work for obstructions. Please contact the Technical Service Department at 800-637-1453 if you need further assistance.
Date published: 2016-11-14
What is the longest acceptable vent pipe length for the QTR080?
Do bends in the exhaust pipe impact the vent's capability to move exhaust air?
Thank you for your question on the model QTR080 exhaust fan. Using four inch rigid duct work, the QTR080 will handle up to 23 feet of straight duct work. You would need to reduce that distance by four feet for every elbow.
Date published: 2014-12-05