dominus_aranearum t1_j9rt17c wrote
If you want to use the current ducting, you need a fan that moves less air. Code-wise, you are not allowed to reduce the duct size coming out of the fixture.
rayw1983 OP t1_j9sdm3s wrote
Oh really? I’ll take a look online for some that fit my current ducting. So the adapter I put on it is not meant for this type of application?
Would you know the concern for reducing the size of the duct?
The odd thing is that some of these exhaust fans come with the adapter.
dominus_aranearum t1_j9serak wrote
Not sure why the fan would come with the 3" to 4" adapter unless the fan output 3" and you were attaching to a 4" duct. Or it is a fan with adjustable CFM settings, one of which was low enough for a 3" duct.
The concern is that you will overwork the fan motor and shorten it's life. You also get the problem you described.
rayw1983 OP t1_j9sfb08 wrote
The fan output is 4”, I wish I had the opposite problem but it does seem to be a 4” to 3” reducer. Here’s the official Panasonic one;
It does have adjustable settings so I’ve set it to 50cfm but has options for 80 and 100. Honestly even on the 50 setting the noise level seems almost the same as the other settings.
dominus_aranearum t1_j9smtpk wrote
So, your fan isn't coming with a reducer like I was thinking. It comes with an adapter to go from a 4" oval to 3" round duct. The area of the both sides is probably very similar but without knowing the width or height of the oval, I can't be certain. This fan is designed to work with this adapter.
Your air blowback could be due to duct blockage or otherwise reduced throughput. Typically, there are maximum duct lengths and number of elbow (bends) allowed before throughput is reduced. Without putting eyes on your ducting, you've really no way to know. I don't know if HVAC companies will scope your duct or not, but I'm fairly certain they can clean them.
Viewing a single comment thread. View all comments