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Air conditioner vibration

Turned on the front AC unit to test. I have a lot of vibration coming through the ceiling. Pulled the covers and had the DW turn it on. I can see a lot of vibration coming from the motor which has a squirrel cage fan on either side. Has anyone else had this issue? Any one know of any parts numbers for replacement ? It looks like it should be a reasonable repair to make.

Thanks for any help in advance.

Larry 
Larry Warren
1996  U320 36' SBID "Lola" sold 2020
Build #4970
Motorcade #18318

Re: Air conditioner vibration

Reply #1 –
If it hasn't been used for a while might check for mud dauber nests on the exposed squirrel cage. I had that very thing happen to me.
previous 1984 35 ft ORED 250 HP 3208 Cat       
previous 1998 40 ft U295 CAI 325 hp Cummins
previous 2003 40 Ft u320 build #6140 450 Cummins M11.                                                         
1999 Mazda Miata
Ron, Nancy, Tipper the cat, Max The dog
1997 U 270 36 ft build number 5174 8.3 Cummins

Re: Air conditioner vibration

Reply #2 –
That was what I hoped to find, but alas the fans were reasonably clean. When I had run the AC 2 months ago there was no vibration. It still puts out cold air, just excessive vibration.

Larry
Larry Warren
1996  U320 36' SBID "Lola" sold 2020
Build #4970
Motorcade #18318

Re: Air conditioner vibration

Reply #3 –
might check the motor mounts still sounds like something throwing it out of balance.
previous 1984 35 ft ORED 250 HP 3208 Cat       
previous 1998 40 ft U295 CAI 325 hp Cummins
previous 2003 40 Ft u320 build #6140 450 Cummins M11.                                                         
1999 Mazda Miata
Ron, Nancy, Tipper the cat, Max The dog
1997 U 270 36 ft build number 5174 8.3 Cummins

Re: Air conditioner vibration

Reply #4 –
Mud. Dubber
George Ray 1992 U280 40'

Re: Air conditioner vibration

Reply #5 –
Red tractor, I agree. It turns smoothly and easy by hand but vibrates bad with electricity. I will open it back up and inspect with a mirror. I didn't notice any play in the shafts or end runout. Something knocks it out to where the fan rubs the cage housing.
Larry Warren
1996  U320 36' SBID "Lola" sold 2020
Build #4970
Motorcade #18318

Re: Air conditioner vibration

Reply #6 –
Squirrel cage blower will vibrate if out of balance. Metal clips are often attached to a blade to balance. Also oil motor bearing with Zoom Spout Oiler may help.

Re: Air conditioner vibration

Reply #7 –
You might take the inside cover off and snug up the mounting bolts it you haven't checked them in awhile.
Bruce, Linda, and Macy
Zoey RIP 1/20/19
1999 U295 40' build #5400
2017 silver Jeep Wrangler, 1260 watts of solar on top
Moving around the country

Re: Air conditioner vibration

Reply #8 –
On my AC unit it was the plastic condenser blower wheel that was deformed, replace with an metal one and problem was solved.
2001 U320 40' IF$ Build #5798
2018 Jeep Grand Cherokee Trailhawk Toad
2015 GMC Duramax HD2500 Toad
2014 Polaris RZR 1000
Litchfield Park, AZ- Soon to be Paulden, AZ

Re: Air conditioner vibration

Reply #9 –
Quote
might check the motor mounts still sounds like something throwing it out of balance.

That was the problem on one of the Fixed it.
jor
93 225
95 300
97 270
99 320

Re: Air conditioner vibration

Reply #10 –
I did check the mounting bolts. They were all tight. There was a lot of movement on the rubber isolaters when it was running.

Larry
Larry Warren
1996  U320 36' SBID "Lola" sold 2020
Build #4970
Motorcade #18318

Re: Air conditioner vibration

Reply #11 –
Quote from: ohsonew –
Red tractor, I agree. It turns smoothly and easy by hand but vibrates bad with electricity. I will open it back up and inspect with a mirror. I didn't notice any play in the shafts or end runout. Something knocks it out to where the fan rubs the cage housing.
Try moving wheel to center it in the housing. Is it tightly secured to the shaft with an Allen screw or did someone substitute a bolt. Does it have 2 inlets or one? Mine has two and a combination of slightly bent sheet metal and loose insulation was blocking inlet airflow on one side.
Old Phart Phred, EIEIO
89 GV ored 36' #3405 300 hp cat 3208 ATAAC side radiator, mountain tamer exhaust brake

Re: Air conditioner vibration

Reply #12 –
Look closely. You might see a oil port on the fan shaft. Our 1989 & 1992 Dometics have oil ports and they are marked "OIL"
Nitehawk,  Demolition Lady, & our NEW master, Zippy the speeding BB cat.
1989 Grand Villa 36' ORED
Oshkosh chassis, 8.2 DD V8
2006 Saturn Vue AWD

Re: Air conditioner vibration

Reply #13 –
But sometimes they are marked "710". LOL
Old Phart Phred, EIEIO
89 GV ored 36' #3405 300 hp cat 3208 ATAAC side radiator, mountain tamer exhaust brake

Re: Air conditioner vibration

Reply #14 –
I thought I remember learning that it is not good to snug up the mounting bolts too tight, as that transfers the vibration to the coach. Maybe too tight is the problem!
Carol & Jeff Savournin
Usta have a '93 U225 36', Usta have a '95 U320 40', Usta have a '02 U320 40'
Usta have a 2006 Born Free, Usta have a 2011 Phoenix Cruiser
Usta have a 2012 Jeep Wrangler Unlimited 4dr
"Your time is limited, so don't waste it living someone else's life."  Steve Jobs

Re: Air conditioner vibration

Reply #15 –
Thanks for all the input, I will be checking this weekend when I can get back down to the rig. Carol, I agree that to tight would definitely transfer the vibration, but this just started. It has been as quiet as the back one for the last 3 years.

Larry
Larry Warren
1996  U320 36' SBID "Lola" sold 2020
Build #4970
Motorcade #18318
 

Re: Air conditioner vibration

Reply #16 –
Just a follow up. Finally got to look at the AC. Found several cracked blades from the outside of the cage housing on the exhaust squirrel cage fan. Figured that has thrown it out of balance. Managed to look inside, and low and behold, just as predicted by Red Tractor and George, a small mud dauber nest on the inside. Cleaned it out and it runs smooth as silk again. Thanks guys. If it weren't for the collective knowledge of this forum and it's members this fun journey would never be possible. Eternally in debt to all of you.

Larry
Larry Warren
1996  U320 36' SBID "Lola" sold 2020
Build #4970
Motorcade #18318