Noisy Air Conditioner


  #1  
Old 08-09-12, 04:15 PM
S
Member
Thread Starter
Join Date: Aug 2012
Posts: 4
Upvotes: 0
Received 0 Upvotes on 0 Posts
Noisy Air Conditioner

I am having a strange sound coming from my furnace/ blower/ etc.. I can turn my fan on from thermostat everything is fine. I can turn on furnace and everything is fine. When I turn on the AC the blower??? is making a squealing noise. I can't seem to pin point where it is coming from. Could it be a noisy bearing on blower motor? I was thinking that, but I would think that the noise would also be present when furnace and fan were running. Thanks for any help.
Dave
 
  #2  
Old 08-09-12, 06:47 PM
E
Member
Join Date: Feb 2010
Location: usa
Posts: 564
Upvotes: 0
Received 0 Upvotes on 0 Posts
furnace and fan use different fan speed than ac. thats why only in ac. Can you lubricate the motor? Are there ports for it?
 
  #3  
Old 08-09-12, 07:03 PM
S
Member
Thread Starter
Join Date: Aug 2012
Posts: 4
Upvotes: 0
Received 0 Upvotes on 0 Posts
Ender, that is what I was thinking. The motor is a four speed motor, I wonder if the higher fan speed for the a/c is producing the noise. The motor bearings could be making the high pitch whining noise under more RPMs? The motor is barely five years old, and doesn't have any grease fittings or any visible ways to lubricate. Thanks, Dave.
 
  #4  
Old 08-11-12, 03:32 AM
P
Member
Join Date: Aug 2012
Posts: 52
Upvotes: 0
Received 0 Upvotes on 0 Posts
Check to see if the sound is coming from the outdoor condensing unit fan. The outdoor unit only comes on in A/C mode if it is a straight cool unit. It would be very unusual for your indoor fan to squeal only on one speed if dry bearings were the issue.
 
  #5  
Old 08-11-12, 11:29 AM
S
Member
Thread Starter
Join Date: Aug 2012
Posts: 4
Upvotes: 0
Received 0 Upvotes on 0 Posts
Podunk, the noise is definitely coming from the furnace/blower area. I am totally at a loss here. I took the blower out of the furnace and ran the a/c and there is no noise. Once I put the blower back into the furnace and ran a/c, the noise returned.
 
  #6  
Old 08-11-12, 01:22 PM
HVAC RETIRED's Avatar
Member
Join Date: May 2008
Location: Wisconsin USA
Posts: 664
Upvotes: 0
Received 0 Upvotes on 0 Posts
If it is a PSC blower motor; removing the blower from the furnace removes the static pressure of the duct system & will result in the blower overloading & therefore running at a lower RPM than it would when in the furnace.

Therefore, at the higher RPM when in the furnace - it would squeal again.
 
  #7  
Old 08-11-12, 06:20 PM
S
Member
Thread Starter
Join Date: Aug 2012
Posts: 4
Upvotes: 0
Received 0 Upvotes on 0 Posts
Thanks HVAC, it is indeed a PSC blower motor. I wasn't sure if removing it would make a difference or help me figure out where the noise is coming from.
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: