Why Blower wheel failure (noise)
See pix please.
I have an old heat pump. after 20 years the blower wheel got noisy. Replaced it in 2002. That Lasted til 2004 ( I went back to same parts store and bought another one- oddly this one had the same manufacture date as the one I bought in 2002 (date was 2001. ) this wheel failed this week and I went and bought a name brand wheel (lau brand from Grainger). the other two were unmarked- had an HQ number on them- maybe a bad batch .
what causes the wheels to fail?- failure was that it started making a rasping metallic noise (wheel was not hitting anything tho, and nothing was stuck in it- I took the motor and wheel out together and ran it in “free air” and it was still noisy. motor bearings are Ok so its not wobbling.
In the pix the end of each vane is crimped by the bottom and top rings. i think thats where it fails (gets loose) and then rattles. I thought about sitting the bottom of the wheel in paint for 10 min to fill up all the little crimp areas but a new wheel was $31 so I bought one.
Any ideas where the noise comes from ?
thanks.
Edited 8/22/2006 8:37 am ET by edwardh1
Replies
I suspect the sound is from the arbor in the motor. Look closely at the motor and you may find plugs that you can remove to add oil. You may have to clean dust and grease off the motor to find the oil holes.
"Any ideas where the noise comes from ? "
The motor, not the wheel, is most likely the problem. Kinda like a grease seal that "fails". The seal fails because the bearing behind it is shot. The wheel makes noise because the motor is shot (most likely).
end of each vane is crimped by the bottom and top rings. i think thats where it fails (gets loose) and then rattles
Pretty sure you are correct in the above diagnosis. Had the same problem, motor and bearings were all quiet. After about 8 years on the original fan, it started to have a tiny rattle that grew worse with time.
Finally took the Squirrel cage out and peened and brazed all the crimped areas and every bit of noise went away. Has held good for the last 13 years now.
PS: once tried to run a squirrel cage at 50% faster than its design speed for a sawdust vacuum - air forces at speed bent all the blades - into a smooth can! That didnt work!.
Edit PS: as others stated, the motor or fan bearings can also make noise if it goes dry, but I assumed that was the first thing you checked and have kept the motor oiled and the filters clean. Ball bearings can also make noise after 10 or so years due to brinnelling, but it is a different sound that the rattle of a loose fan (more of a growl).
Edited 8/22/2006 2:10 pm ET by junkhound
I had a forced air furnace blower that had a bit of oil on it. After 5 years the oil spot accumulated dust and dirt which made it unbalanced. The vibrations broke the motor brackets which made the squirrel cage rub and squeal.
Hey guys I think the motor has always been ok
based on when I changed the wheel (3 times now) the noise goes away for two years.I think I got 2 bad wheels from a no name probably mexican source at the HVAC parts place.
the new wheel has a brand name on it at least