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Need help with Trane XB80 vibration!

9K views 14 replies 6 participants last post by  REP 
#1 ·
Hello all, I'm no repairman or really good at DIY projects, but with my google-fu skills being strong, I have managed to fix odds and ends with my furnace and central AC unit in the past.

I have a Trane XB80 furnace. It was installed by friends who worked for an HVAC company back in the summer of 2004. I've never had any problems with it until I punched my thermostat (I know, pretty stupid of me!) and shorted something out in the furnace which I ended up fixing. That was years ago. Besides that, I've had no other problems with it.

Over the summer, I ran the AC constantly. I never had any loud noise or vibration. Today when I got home from work, it was a little warmer out so I decided to put the AC back on. The last time I ran it was a few weeks ago. Anyway, out of nowhere it is vibrating like crazy. When I push on the side of furnace down by the blower, the vibration ceases to exist and virtually disappears, back to an unnoticeable level. Before I rip everything apart, does anyone have any suggestions as to what could be wrong, so I have somewhere to focus on. Obviously I know the vibration is coming from the blower/fan/housing(whatever it's called), but I'm not sure if something came loose that needs to be tightened, or if something is worn out with the blower itself. The diagnostic light is blinking slowly which is normal, according to the diagnostic guide. Thank you for your help!

Oh yeah, i have never taken anything apart and cleaned it, only the furnace filter. When I punched the thermostat, all that involved was changing out some electrical component right behind the service panel.
 
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#2 ·
Since you're so good with your hand.....you can use a hammer to fix this problem. :thumbsup:

It may be the bearing of the fan motor, motor loose or the blades are touching something
 
#6 ·
The blower is secured to a piece of sheet metal above it. There are screws going into the side of the furnace that screw into this piece of sheet metal. One of them is stripped, for the most part. It tightens down a little, but keeps turning after a certain point. It's when I mess with the stripped screw (by either pressing against the furnace there or just by loosening or tightening the screw), that's when the vibration will get louder, or die down. I'm guessing something came loose. But I will take everything apart to check. I'm glad the problem hit now and not in December!

Once I get the parts out I will post some pics so hopefully that will help in pinpointing the problem.
 
#9 ·
Cool, thank you fellas for the suggestions. Gonna tackle this project tomorrow, and I will post some pics if need be.

It's just weird how I didn't use my AC for a few weeks, and the first time I turn it back on is when the vibration started out of the blue.
 
#12 · (Edited)
OK, finally getting to this problem 2 months later. Whoops!
Anyhow, blower is removed from the furnace. Should there be side to side play in the fan? There is maybe a 1/4 of an inch of play. I wonder if that is where the vibration is originating from.

I'm gonna tinker with this thing for an hour or two, and if no luck, off to the DIY hvac store I go. they can probably shed some light on things. Thanks.

EDIT: Actually it is more like 1/8 inch of play. I can't see how to try and tighten the fan/blower (whatever it's called), but it looks like the housing may be behind the motor, which i'm going to take off.
 
#13 ·
Problem solved. All it needed was a good cleaning, I guess. I cleaned the hell out of the blower, housing and blower motor. The entire blower was dirty, but on the one side is where all the crud was, and I'm pretty sure that all that gunk on that side of the fan was throwing it out of balance and causing the vibration which had been driving me crazy. Everything is put back together and no noise. Hopefully it stays that way!
 
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