Calling all bathroom fan experts

[Jeff7]

I'm in a college campus apartment, and they cheap out on just about everything they can. The problem right now is the bathroom fan. They use this kind of blower. It's plastic. Thin plastic. Weak plastic. Unbalanced plastic.
The blower is lopsided - as it rotates, it very visibly wobbles, and it does so right out of the package. It lasts up to 4 months. The latest one has been in place for less than 2 months, and it's already cracked where it slides onto the motor shaft, and there are signs of stress at the reinforcing spokes immediately around it. This makes the thing very loud, like having a motorcycle idling in the bathroom ceiling, and the motor gets very hot. I don't know exactly how loud it is in decibels, but it's at least as loud as a Dremel grinding at wood, only lower frequency.

So the question to ATOT's many, many bathroom fan experts: Is there anywhere I can get a metal replacement blower for this? Do they even make such a thing?
Maintenance won't replace the blower until it's completely busted loose and scraping against the rest of the unit's frame.

The only thing I have planned in the meantime is to install soft rubbery grommets where the motor mounts to the frame, so at least I can prevent so much vibration from getting into the framework of the apartment. It's possible to stand in the next room and easily feel when the fan is on or not, that's how bad it is.
I shall add too, the plastic may be nylon. Or not, but whatever it is, Plastic Welder (or anything similar) can't bond to it.


While you're here, check out my LED candle question thread too.

 

[Evadman]

squirel cage blowers have major issues. You need to convince them that a better more expensive fan will last. They should last for manty many years. $50 every 6 months is more money than $500 every 10 years. A good fan is < 200.

 

[Jeff7]

The maintenance guys know that they suck. They say that replacing bathroom fans is probably the most common thing they do in the apartments. The problem would be convincing whoever is responsible for buying the parts. There is talk of consideration of plans to possibly perhaps renovate the apartments. They're kind of showing their age.

At home, the one bathroom fan probably cost less than $100, and it was installed over 2 years ago. I'm not sure though what its blower is made out of. Whatever it is, it's fairly quiet.
And an old air conditioner I took apart has the same kind of blower. It developed some other problem though, and it wasn't spitting the water out the back properly, so I drilled a drainage hole in the base, now it works fine. But the blower was all damn nasty with mold. Bleach and a light pressure washing did the trick.
Anyway, the air conditioner is over 10 years old, and the blower, also nylon, is still in fine shape. Why? It's balanced very well, and was apparently made to tight geometric tolerances. It's also a lot thicker where it's stressed the most - the mounting hole. The reinforcing ribs are also thickened.

I guess nylon can do the trick. Problem is, Nutone cheaped out, and made it thinner than it should be, with some pretty lax geometric tolerances.


Note - I'm fairly sure that this stuff is nylon. It could be high density polyethylene or polypropylene though. The only tests I know of to determine what kind of plastic something is involve burning some of the sample. Maybe I'll do that when they have to replace this blower.

 

[Jeff7]

Bump up again.

My roommate and I are considering just buying another unit. Of course, housing might not like it, since they wouldn't have the right replacement parts.

 

[Rubycon]

You may be able to seek a replacement from Lau that will fit but just because it fits doesn't mean it will work - in the long run.

If the pitch is not the same the motor will be overloaded and with increased slip comes more current. More current = overheating so it won't run long before the bimetal device buried in the windings opens.

A metal wheel will exert more stress on the sleeve bearings. This will cause longevity problems and increased play so one day it will start rubbing on the housing making a horrid noise.

The best bet is to purchase a decent blower. Broan is a good brand. Better brands not only move more air at a given static pressure but will do so quietly.

 

[Jeff7]

I figure that the motor is already overloaded. It's hot as hell after being on for awhile, and the shaft keeps knocking against the back of the motor with each rotation. I can't imagine that the off-balanced impeller is good for the motor.

Broan seems to be affiliated with, or is the same company as, Nutone, which is what's in there now.

 

[Rubycon]

Originally posted by: Jeff7

Broan seems to be affiliated with, or is the same company as, Nutone, which is what's in there now.

JBL, Harmon Kardon, and Jensen are all the same too.

 

[Jeff7]

Originally posted by: MS Dawn

JBL, Harmon Kardon, and Jensen are all the same too.

Jeff7, quiet and embarrassed, looks shiftily back and forth

Um....who?

A metal wheel will exert more stress on the sleeve bearings. This will cause longevity problems and increased play so one day it will start rubbing on the housing making a horrid noise.

Good, if the motor finally dies, maybe they'll get the hint and stop using cheap junk. But I doubt it.


So this Lau place, how does one actually purchase one of their products?

 

[danzigrules]

Originally posted by: Jeff7
I figure that the motor is already overloaded. It's hot as hell after being on for awhile, and the shaft keeps knocking against the back of the motor with each rotation. I can't imagine that the off-balanced impeller is good for the motor.

Broan seems to be affiliated with, or is the same company as, Nutone, which is what's in there now.

sounds to me like the shaft is bent or it has bad bearings

 

[Jeff7]

Originally posted by: danzigrules
sounds to me like the shaft is bent or it has bad bearings

Nope, without the blower on, the motor runs beautifully, and almost dead silent with very little vibration at all.
Put the blower on, and it sounds like hell, and the whole unit vibrates like crazy. The blower is off center on two axes - it wobbles up and down as it rotates, and it looks like it's either out of round, or unbalanced.

 

[TG2]

if its unbalanced, can you try sanding it in the heavy areas?

id try to put in some other type of blower that will fit the current opening, then when you leave, put the original one back in

 

[Rubycon]

Originally posted by: Jeff7

Originally posted by: danzigrules
sounds to me like the shaft is bent or it has bad bearings

Nope, without the blower on, the motor runs beautifully, and almost dead silent with very little vibration at all.
Put the blower on, and it sounds like hell, and the whole unit vibrates like crazy. The blower is off center on two axes - it wobbles up and down as it rotates, and it looks like it's either out of round, or unbalanced.

Hehe if the blower wheel was bigger you could put it on this.

 

[Jeff7]

Originally posted by: MS Dawn
Hehe if the blower wheel was bigger you could put it on this.

Heh, indeed. Though it depends on how much of a balancing error that machine can handle. This thing's balance sucks so much that it might push that machine's limits.


So this Lau place - is it in fact possible to purchase things from them, or do they only sell in bulk to dealers?

 

[Rubycon]

Originally posted by: Jeff7


Heh, indeed. Though it depends on how much of a balancing error that machine can handle. This thing's balance sucks so much that it might push that machine's limits.


So this Lau place - is it in fact possible to purchase things from them, or do they only sell in bulk to dealers?

Send an email to Hunter and see if they recommend spinning a tire that's been half filled with seawater!

Try this place for parts.

 

[Jeff7]

An update on this thread, finally.

I checked into the price of a replacement blower, a metal one.
Two problems:
1) They want $40 for it, plus shipping. A new bathroom fan would cost less than that.
2) They didn't have a bushing that'd bring the 1/2" bore on the blower down to fit on a 1/4" shaft.


I did make a few modifications on the bathroom fan though that is in place. I put in a few rubbery grommets between the motor and the frame. Now the fan can rip itself to pieces, but it transfers very little of the vibration to the frame of the building, so at least the sound doesn't resonate from the walls now. (Now I just have left to deal with the horrendously bass-heavy guitar noise from next door, and the bad music from the people above me and on the other side of the room.:roll: )
I also smeared some plastic epoxy around the cracked center of the blower. I probably should have just busted it off completely. Maintenance won't replace it until it's completely busted off.
But the grommets may have caused another "problem" - they might have extended the life of this noisy, damaged blower. By allowing the motor some motion, this could lessen the stresses on the center of the blower. While this would be good to prolong the life of good blowers, it also means I've got to either put up with the noise longer, or else be a little unethical and make the thing be broken.