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View Full Version : Sorta OT: Finally, a fix for those blasted noisy and ineffective bathroom vent fans



winchman
08-20-2010, 11:03 AM
It involves a vice and a file, so I'm going with it. :D

As anyone that's read most of my posts here knows, I have a real dislike for unnecessary noise. Dogs barking at nothing, refrigerators, fluorescent light ballasts, etc, really get my ire up.

Well, one of the worst is the bathroom fans in our house. They howled and vibrated to no end. A complete disassembly revealed nothing obviously amiss. The fan ran quietly when out of the housing, the discharge damper was working fine, and the discharge duct was clear. Just like it was supposed to be.

Then I noticed how far the fan fit into the housing. It was all the way to the end of the shaft and close to the top of the housing. That put the outflow from the rotor directly on the top of the damper (the part that swings in), which kept the damper from opening. That reduced the flow to near zero, so the motor spun much faster than normal causing much turbulence, vibration, and noise.

The rotor hub has a internal flat to match the one on the shaft. It slips on, but would only go down to the end of the flat on the shaft, which wasn't very far.

So, I got the trusty file, chucked the shaft in the vice, and made the flat about 3/8" longer so the rotor would be closer to the motor. Of course, the rotor then hit the plastic endcaps on the coil, but some quick work with a sanding block fixed that.

Now the rotor outflow is lower on the damper, so the damper opens completely. The airflow is much better, the motor runs at it's normal speed, and the noise is less than half of what it was before. Using the bathroom just got a whole lot nicer.

EddyCurr
08-20-2010, 11:47 AM
Time to catch up on articles from back issues of HSM.

.

Guido
08-20-2010, 12:08 PM
Hey, Mr. Curr---------Winchman might just explain his method of fixing the seatbelts in his pickup.

I doubt if HSM has taken that little noise problem to task !

--G

Too_Many_Tools
08-20-2010, 03:15 PM
It involves a vice and a file, so I'm going with it. :D

As anyone that's read most of my posts here knows, I have a real dislike for unnecessary noise. Dogs barking at nothing, refrigerators, fluorescent light ballasts, etc, really get my ire up.

Well, one of the worst is the bathroom fans in our house. They howled and vibrated to no end. A complete disassembly revealed nothing obviously amiss. The fan ran quietly when out of the housing, the discharge damper was working fine, and the discharge duct was clear. Just like it was supposed to be.

Then I noticed how far the fan fit into the housing. It was all the way to the end of the shaft and close to the top of the housing. That put the outflow from the rotor directly on the top of the damper (the part that swings in), which kept the damper from opening. That reduced the flow to near zero, so the motor spun much faster than normal causing much turbulence, vibration, and noise.

The rotor hub has a internal flat to match the one on the shaft. It slips on, but would only go down to the end of the flat on the shaft, which wasn't very far.

So, I got the trusty file, chucked the shaft in the vice, and made the flat about 3/8" longer so the rotor would be closer to the motor. Of course, the rotor then hit the plastic endcaps on the coil, but some quick work with a sanding block fixed that.

Now the rotor outflow is lower on the damper, so the damper opens completely. The airflow is much better, the motor runs at it's normal speed, and the noise is less than half of what it was before. Using the bathroom just got a whole lot nicer.

Did you know that bathroom fans are meant to be noisy to cover up the noise one makes on the toilet? ;<)

TMT

photomankc
08-20-2010, 04:20 PM
Did you know that bathroom fans are meant to be noisy to cover up the noise one makes on the toilet? ;<)

TMT


I hate when there is bathroom that sits in stoney silence just through the wall from where everyone sits and talks. You just know the tacos and bowl of ice cream you crammed down is going to be audible event in an hour or two.

oldbikerdude37
08-20-2010, 04:38 PM
LOL a fart fan is very valuable that's for sure. im going to upgrade ours soon.

rockrat
08-20-2010, 04:46 PM
If your that fussy about the noise, just turn on some water in the sink.

Makes them think that your washing your hands! :D

I do have to ask winchman, was that a standard exhaust fan? I installed one when we bought the house and I think over time it has become more noisy. Was your fan quiet when first installed?

rock~

Too_Many_Tools
08-20-2010, 05:53 PM
If you want quiet, try this.

Years ago I was in an Amish household and used their toilet.

Down low on the wall behind the toilet was a large PVC pipe opening.

It turns out it was an intake to a small chimney that was vented to the outside.

Its draft was set up to draw odors from the bathroom.

Ingenious...and dead quiet.

When I build my next house, I plan on implementing the idea.

TMT

Lew Hartswick
08-20-2010, 06:08 PM
It turns out it was an intake to a small chimney that was vented to the outside.

Its draft was set up to draw odors from the bathroom.

Ingenious...and dead quiet.
TMT
That "thermo-siphion" technique is suppose to work very well. Back
in the dimdarkages when I was subscribed to Mother Earth News
there was an article on such a device for cooling a building. It included
a clear window around the vent pipe above the roof to heat the
interior of the vent and promote the convection. Only problem I
see is WINTER time. :-)
...lew...

Doozer
08-20-2010, 06:26 PM
Twice now, when I was having an explosive moment in the bathroom at work, my boss comes out of the stall next to mine, and, well, it just adds to the list of things about me that are not normal.

--Doozer

Too_Many_Tools
08-20-2010, 06:47 PM
That "thermo-siphion" technique is suppose to work very well. Back
in the dimdarkages when I was subscribed to Mother Earth News
there was an article on such a device for cooling a building. It included
a clear window around the vent pipe above the roof to heat the
interior of the vent and promote the convection. Only problem I
see is WINTER time. :-)
...lew...

I asked my host about how they cover the "noise in the bathroom" and he said that they sing hymns. ;<)

TMT

Your Old Dog
08-20-2010, 06:51 PM
If your that fussy about the noise, just turn on some water in the sink.

Makes them think that your washing your hands! :D

...................................

Not exactly. It makes them wonder why you didn't use toilet paper to wipe with instead of your bare hands.

**********************************************



If you want quiet, try this.

Years ago I was in an Amish household and used their toilet.

Down low on the wall behind the toilet was a large PVC pipe opening.

It turns out it was an intake to a small chimney that was vented to the outside.

Its draft was set up to draw odors from the bathroom.

Ingenious...and dead quiet.

When I build my next house, I plan on implementing the idea.

TMT

Well I've dropped a couple loads into them as well. Any silence gained by the use of PVC pipe instead of a fan is soon lost when your turd drops some 30 feet below and splashes like a small wale at Marine Land. At that point you walk out of the bat room, do a Tarzan Zerbini yell and proclaim you gave it the name of Edgar before sending him on his way...

rohart
08-20-2010, 06:55 PM
Rock - I think all fans get noisier as they get old because the surfaces of the blades get condensates and dust stuck to them, which increases the turbulence, and that's where the noise comes from, apart from motor and bearing noise that is.

If you take your computer apart and clean the fan blades carefully it gets a lot quieter.

Just clean the s**t off the fan, and there you are.

wtrueman
08-20-2010, 11:49 PM
Hey Doozer: Remember the old days when the outhouses had two seaters? Can you think of your boss enjoying page 234 of the sears catolog before you needed it?

Mike Burch
08-21-2010, 02:38 AM
What a wonderful thread!
Worried about the noises you make on the loo? Try living on a yacht or a campervan (RV) for a while - trust me, you'll soon get over that particular inhibition, and learn to be a sharer.
As for fan noise, well, our last house had big effective fans which were almost silent when installed, but after a couple of years became noisier and noisier. Cleaning the crud off the blades helped, but the real problem was that the rubber do-hickies that were supposed to isolate the fan from the tube the whole thing was mounted in became hardened with age, and ceased to do any damping of the vibrations. So the vibrations were transferred without much loss to the frame of the house. The noise level became quite ridiculous. And of course the manufacturers wouldn't sell the rubber bits as spares...
Added to that was the problem of the louvres which were supposed to stop any draughts when the fan was switched off. Boy, did they make a clatter in a northerly!
In our new house, the electrician initially (and against my specific instructions) fitted a fan halfway along a duct, in a section of ceiling that was going to be impossible of access once the house was finished. When it inevitably broke down it would therefore have been impossible to repair or replace it. Fortunately I caught the problem in time, and got him to fit all the extractor fans right there in the ceiling lining where I can get at them.

BWS
08-21-2010, 07:50 AM
TP holder intregal w/magazine rack is a wrthwhile woodwackin project.Heck,you can visit the machineshop as well if you custom make the roll holder with turned ends.

My shop bathroom is cool,got several Deer racks mounted along with a host of huntin magagzines.BW

winchman
08-21-2010, 08:51 AM
"Was your fan quiet when first installed? "

I don't know. The house was twenty years old when we bought it, but I don't see how it could ever have been quiet with the rotor positioned like that.

I suppose it's possible the motor was replaced with one that didn't really match the original. Things like that happen.

I never said anything about me making noise in the bathroom or using the fan to cover for me. I just didn't like listening to the noisy fan right over my head when I was showering or using the john.

Too_Many_Tools
08-21-2010, 01:39 PM
TP holder intregal w/magazine rack is a wrthwhile woodwackin project.Heck,you can visit the machineshop as well if you custom make the roll holder with turned ends.

My shop bathroom is cool,got several Deer racks mounted along with a host of huntin magagzines.BW

One of the BEST additions I have ever seen to a bathroom was in a small one man shop.

He had made a swivel shelf that swung over in front of the throne.

On that shelf...was a Sherline lathe.

While he was sitting on the throne, he would do some turning.

I still laugh thinking about it.

TMT

winchman
08-21-2010, 02:21 PM
I always thought the phrase "turning and burning" was a good thing, but now...

doctor demo
08-21-2010, 10:13 PM
Well I've dropped a couple loads into them as well. Any silence gained by the use of PVC pipe instead of a fan is soon lost when your turd drops some 30 feet below and splashes like a small wale at Marine Land.

Y O D , You must have trouble climbing up on that 30' toilet:D , and not to mention how hard it must be trying to stand in front of it and take a leak with out making a mess or gettin wet.

Steve