York A/C unit pops and the buzzes, condenser fan doesn't spin

Reply

  #1  
Old 06-27-14, 05:31 PM
mrfirmware's Avatar
Member
Thread Starter
Join Date: Jun 2014
Location: USA
Posts: 6
Received 0 Votes on 0 Posts
Question York A/C unit pops and the buzzes, condenser fan doesn't spin

I've read a bunch of posts here but not found a problem that is similar enough to help me figure this out. Hopefully someone can help me.

My A/C unit makes a loud pop and then buzzes. Buzzing does not seem to be the condenser fan or the compressor but in the area of the A/C unit's electronics panel. I have replaced the cap and the behavior is the same so that wasn't the problem. The circuit breaker trips but oddly not "all the way" and the buzzing continues until the thermostat is told to stop asking for cooling (me screaming at my wife to shut it off). The coils look clean, the condenser fan spins freely by hand. There was a wire that had shorted to the A/C unit's frame. I repaired the exposed wire but still no joy. There's a fair amount of rust where the electronics are in the small corner panel of the A/C unit and I had to clean out a mouse nest that was in there. I've include pictures of the unit, the model info sticker, and the cap I replaced for reference. Any help much appreciated.

Name:  photo1.jpg
Views: 590
Size:  40.4 KB

Name:  photo2.jpg
Views: 757
Size:  45.2 KB

Name:  photo3.jpg
Views: 456
Size:  34.5 KB
 

Last edited by PJmax; 06-27-14 at 06:29 PM. Reason: reoriented pics
Sponsored Links
  #2  
Old 06-27-14, 05:34 PM
mrfirmware's Avatar
Member
Thread Starter
Join Date: Jun 2014
Location: USA
Posts: 6
Received 0 Votes on 0 Posts
Post

Sorry the pictures are sideways and upside down.
 
  #3  
Old 06-27-14, 05:38 PM
C
Member
Join Date: Aug 2008
Location: Texas, California
Posts: 1,471
Received 0 Votes on 0 Posts
Can you take a picture of the contactor, that may be your problem.
 
  #4  
Old 06-27-14, 05:42 PM
Houston204's Avatar
Forum Topic Moderator
Join Date: Oct 2009
Location: Texas
Posts: 7,426
Received 17 Votes on 14 Posts
The buzzing is your contactor but it is unlikely that the contactor is tripping the breaker.

Do you have an Ohm meter to test the compressor and crank case heater? If not you can visually inspect the compressor terminals and the crank case heater then isolate them one at a time and try to reset the breaker.
 
  #5  
Old 06-27-14, 05:44 PM
mrfirmware's Avatar
Member
Thread Starter
Join Date: Jun 2014
Location: USA
Posts: 6
Received 0 Votes on 0 Posts
Post

Sure thing. I'm out of light tonight but I'll post picture tomorrow. Thanks.

I do have a DMM.
 
  #6  
Old 06-27-14, 07:19 PM
CasualJoe's Avatar
Member
Join Date: Jan 2010
Location: United States
Posts: 10,557
Received 66 Votes on 57 Posts
The circuit breaker trips but oddly not "all the way
That isn't odd at all. Most circuit breakers trip to a central position leaving the handle loose. Push the handle fully to the "OFF" position and then back to the "ON" position to reset. Circuit breakers will trip either on a direct short or an overload.
 
  #7  
Old 06-27-14, 07:35 PM
Houston204's Avatar
Forum Topic Moderator
Join Date: Oct 2009
Location: Texas
Posts: 7,426
Received 17 Votes on 14 Posts
That isn't odd at all. Most circuit breakers trip to a central position leaving the handle loose. Push the handle fully to the "OFF" position and then back to the "ON" position to reset. Circuit breakers will trip either on a direct short or an overload.
If I had a nickel for every time that I have said this to customers, I'd have a lot of nickels.
 
  #8  
Old 06-28-14, 06:58 AM
mrfirmware's Avatar
Member
Thread Starter
Join Date: Jun 2014
Location: USA
Posts: 6
Received 0 Votes on 0 Posts
Ok, checked out the contactor - it's good. I could here the contacts clicking when I removed/replaced the coil wire. It reads open circuit when not energized and closed when it is energized.

However, the compressor coil read about 0.5 Ohms across the T1C (black wire) and T3R (red wire) leads. Also, the red wire connector and the T3C blade show severe signs of arc welding which implies a short and explains why my breaker keeps tripping. The pop I'm hearing is probably a 220Vac arc. I've attached pictures of the compressor make, the contact ring and the condition of the red wire connector - not good.
 
Attached Images    
  #9  
Old 06-28-14, 08:22 AM
Houston204's Avatar
Forum Topic Moderator
Join Date: Oct 2009
Location: Texas
Posts: 7,426
Received 17 Votes on 14 Posts
That compressor looks like it has a dead short to ground.
Does your meter have a high Ohm range , like millions?
I'd check each terminal to the copper pipe on the compressor.

I'd be surprised if the system didn't blow the charge. Is there oil around the compressor?
I bet the refrigerant smells more like ammonia than WD40 if it is still in the system.
 
  #10  
Old 06-28-14, 10:14 AM
mrfirmware's Avatar
Member
Thread Starter
Join Date: Jun 2014
Location: USA
Posts: 6
Received 0 Votes on 0 Posts
Post

Well I set the DMM to 20M (highest setting) and it read open from T3C to the aluminum braided ground wire. Same reading on T1C. They also read open with respect to the A/C unit's frame. There is no visible leakage anywhere. The compressor and surrounding frame base look dry as a bone.
 
  #11  
Old 06-28-14, 10:46 AM
Houston204's Avatar
Forum Topic Moderator
Join Date: Oct 2009
Location: Texas
Posts: 7,426
Received 17 Votes on 14 Posts
I would try a Quik Lug compressor terminal repair kit.
Clean the compressor terminals with a small wire brush first.
 
  #12  
Old 06-28-14, 03:01 PM
mrfirmware's Avatar
Member
Thread Starter
Join Date: Jun 2014
Location: USA
Posts: 6
Received 0 Votes on 0 Posts
Post

You really think there's anything left of that compressor? I have an HVAC pro coming out to look at it on Monday. I really fear the compressor windings are melted/shorted.

Thanks to all for the great suggestions and help.
 
  #13  
Old 06-28-14, 05:43 PM
Houston204's Avatar
Forum Topic Moderator
Join Date: Oct 2009
Location: Texas
Posts: 7,426
Received 17 Votes on 14 Posts
It is probably toast. You could isolate then ohm common to start, common to run and start to run.

Common to run should be the lowest reading.
Common to start will be a higher reading.
Run to start should be the sum of the other two readings.

Each terminal should be measured to the copper hot gas line.
 
Reply
Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


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