Bathroom exhaust fan not effective

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Spicoli43

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My spare bathroom is 5' x 7.5', and until recently could clear the air after a shower in 20 minutes or so. Now it's taking around an hour.

I figured either critters made a nest in the vent (No) or it was simply a 50 CFM unit or something like that. (It's 110). There is good air flow to the outside of the house as well, with the louvers horizontal.

The fan is turning, the vent is clear, the air is moving. I'm drawing a blank here.

Any ideas?

Thanks.
 

oldognewtrick

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Bathroom door open or closed. Any changes to the house recently? New roof? Any chance you have a humidifier that's not set correctly? Believe it or not, I had a customer that had a new HVAC unit installed and they wired the humidifier to run when the a/c was cycling. Made for some very humid air on the second floor.
 

Spicoli43

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Bathroom door open or closed. Any changes to the house recently? New roof? Any chance you have a humidifier that's not set correctly? Believe it or not, I had a customer that had a new HVAC unit installed and they wired the humidifier to run when the a/c was cycling. Made for some very humid air on the second floor.
Thanks, but no. Bathroom door closed. No changes to the house, one story. I haven't ran a humidifier this year.
 

Jeff Handy

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Put a piece of TP on the grill of the fan, while it’s running.
It should stick if the fan is pulling air.

Maybe the damper inside the fan is stuck closed.

And bath fans can get packed with fuzz and dust.

The guts of the fan will usually unplug and come out easily, so you can clean out the fuzz and check or clean the damper.

The motor might be turning, but not as fast as it used to.

You can get replacement motors at HD or Amazon, or the manufacturer website.
There is usually a model number up in the fan housing, which will tell you what motor you need.
 

Spicoli43

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Put a piece of TP on the grill of the fan, while it’s running.
It should stick if the fan is pulling air.

Maybe the damper inside the fan is stuck closed.

And bath fans can get packed with fuzz and dust.

The guts of the fan will usually unplug and come out easily, so you can clean out the fuzz and check or clean the damper.

The motor might be turning, but not as fast as it used to.

You can get replacement motors at HD or Amazon, or the manufacturer website.
There is usually a model number up in the fan housing, which will tell you what motor you need.
Thanks, It's pulling air, at least 8 sheets of printer paper was no problem.

In inspecting the duct from the outside, it had some dust on the sides, but no blockage.

I'll look into getting a new motor, but something tells me it will be better just to upgrade.

In the meantime, I'll probably get a snake cam that I can use for 500 other things, like finding out if it's true the builder didn't insulate the walls!
 

Jeff Handy

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If the current duct size is three inch, you should upgrade to four inch when installing a new fan.

Assuming you have access to run a new duct.

Meanwhile, it does not make sense that your fan is pulling so well yet the venting has gone way down.
Make sure the flap or louvers on the vent hood are opening easily and all the way.
They get sticky from fuzz and sometimes don’t move properly.

Cutting off a 1/2 inch or so at the bottom of the door will help.
Also, make sure the furnace vent in the bathroom is open, if there is one, the fan can exhaust better if it can pull makeup air from outside the room.

Yes, a snake cam is handy for lots of jobs.
Even going down a drain, inside walls for wiring jobs, etc.
 

Steve123

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It's pulling air, at least 8 sheets of printer paper was no problem.
Sounds like great airflow.
Your memory may be over-estimating how good it worked last year.
You may also want to experiment how much to leave the door open. For every cubic foot of air that exits the bathroom, you need another cubic foot of air to enter the bathroom -- so if you close the door, you are restricting airflow. On the other hand, the fan is likely right in front of the door, so if you leave the door open, you are pulling air from the adjacent room.
 

Spicoli43

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If the current duct size is three inch, you should upgrade to four inch when installing a new fan.

Assuming you have access to run a new duct.

Meanwhile, it does not make sense that your fan is pulling so well yet the venting has gone way down.
Make sure the flap or louvers on the vent hood are opening easily and all the way.
They get sticky from fuzz and sometimes don’t move properly.

Cutting off a 1/2 inch or so at the bottom of the door will help.
Also, make sure the furnace vent in the bathroom is open, if there is one, the fan can exhaust better if it can pull makeup air from outside the room.

Yes, a snake cam is handy for lots of jobs.
Even going down a drain, inside walls for wiring jobs, etc.
That's a good idea if I'm up in the attic. I assume it lays flat on the ceiling, I doubt they even braced it.

I'll do a test and run the fan only on the furnace right after a shower to see if that helps.

I'll check the duct size again, as Lowe's doesn't carry anything 3". maybe it's 4" after all and I just wasn't paying attention.
 

Spicoli43

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Sounds like great airflow.
Your memory may be over-estimating how good it worked last year.
You may also want to experiment how much to leave the door open. For every cubic foot of air that exits the bathroom, you need another cubic foot of air to enter the bathroom -- so if you close the door, you are restricting airflow. On the other hand, the fan is likely right in front of the door, so if you leave the door open, you are pulling air from the adjacent room.
It was 20, 25 minutes max. There is no variable that changed, that's why I'm just ??? besides a complete new replacement. It is 14 years old, so I can't expect it to do much more than that.

I have never kept the door open.
 

Jdeal1

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Put a piece of TP on the grill of the fan, while it’s running.
It should stick if the fan is pulling air.

Maybe the damper inside the fan is stuck closed.

And bath fans can get packed with fuzz and dust.

The guts of the fan will usually unplug and come out easily, so you can clean out the fuzz and check or clean the damper.

The motor might be turning, but not as fast as it used to.

You can get replacement motors at HD or Amazon, or the manufacturer website.
There is usually a model number up in the fan housing, which will tell you what motor you need.
Same issue here. How do I check the damper?m
 

Jeff Handy

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You have to pull out the fan motor, which is mounted on a plate.
The motor usually just unplugs.
Then the plate comes down by removing one screw, or sometimes by just prying one side enough to release tabs that hold it in the square fan housing.
Then the damper will be visible along one side in most fan housings.
It should be able to swing open easily, and shut by gravity when no air pressure or finger pressure is pushing on it.
 

Jeff Handy

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While you have it apart, vacuum all the dust and fuzz you will find up in there.
Vacuum the blower wheel also, and use a paint brush or similar tool to get stuck on fuzz out of it.
The vanes get blocked and also get unbalanced by fuzz getting stuck in there.

Fuzz also commonly causes the lightweight plastic duct damper to stick open, closed, or somewhere in between.
 

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