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Question about the flap inside bathroom ceiling fan

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  • Jan 7th, 2021 10:53 am
[OP]
Member
Jul 6, 2008
210 posts
13 upvotes
Toronto

Question about the flap inside bathroom ceiling fan

I'm currently disassembling a very old bathroom fan that's been squealing. Cleaning it and greasing.

There's a flap inside that swings open when the fan is on and closes when off.
I noticed that this flap is no longer functional as one of the plastic clips that it latches onto broke off.
I don't think there's a way to fix that.

My question is - can I just get by without this flap? Is its main purpose to keep out cold air?
7 replies
Deal Expert
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Feb 11, 2007
16051 posts
17340 upvotes
Oakville
chixdiggit wrote: I'm currently disassembling a very old bathroom fan that's been squealing. Cleaning it and greasing.

There's a flap inside that swings open when the fan is on and closes when off.
I noticed that this flap is no longer functional as one of the plastic clips that it latches onto broke off.
I don't think there's a way to fix that.

My question is - can I just get by without this flap? Is its main purpose to keep out cold air?
Yes, it prevents back draft. You could 3D print a new one if you have a 3d printer or know someone with one. Or just ghetto fix it with some tape.
Deal Fanatic
Mar 21, 2002
6413 posts
1078 upvotes
Yes you can do without it but you will get a cold backdraft coming out of it when not in use. Not an issue in the summer but could be a problem/annoyance in the winter and especially on a windy day.
Deal Fanatic
Jul 7, 2017
6126 posts
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SW corner of the cou…
If you can get some sturdy wire, you could use some epoxy and make a new hinge axis.
Cream rises to the top. So does scum.
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Aug 12, 2007
4685 posts
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Waterloo
chixdiggit wrote: I'm currently disassembling a very old bathroom fan that's been squealing. Cleaning it and greasing.

There's a flap inside that swings open when the fan is on and closes when off.
I noticed that this flap is no longer functional as one of the plastic clips that it latches onto broke off.
I don't think there's a way to fix that.

My question is - can I just get by without this flap? Is its main purpose to keep out cold air?
Without the flap , the cold air coming in from the outside will accumulate moisture on the fan and dust will stick to it.

you need to fix it. or get a new fan or a genuine replacement part from the fan manufacturer.
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Deal Addict
Jan 21, 2018
4603 posts
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Vancouver
A general rule of thumb is that any kitchen or bathroom fan ducted to the outside has a flap to prevent cold air inflow in the winter, and if it's more than a few years old the flap is stuck or broken.

It's a routine home maintenance item to remove the fan every couple of years, check and lubricate the flap to make sure it is working. It should work properly for at least a month or two after that. :rolleyes:
Needless to say, they are generally not well-designed.
Deal Addict
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Sep 27, 2006
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Not so easy there Ma…
thriftshopper wrote: If you can get some sturdy wire, you could use some epoxy and make a new hinge axis.
Or tape and a toothpick or paperclip.
Deal Addict
Nov 17, 2012
3242 posts
2199 upvotes
Toronto
You may also be able to augment/replace the function of that flap with the vent on the side of the house. Where does the fan vent to? Does the exterior vent trim have a flap of its own?

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