A/C compressor fan not starting

Reply

  #1  
Old 06-26-14, 10:06 AM
P
Member
Thread Starter
Join Date: Jun 2014
Posts: 2
Received 0 Votes on 0 Posts
A/C compressor fan not starting

My A/C compressor fan does not start when a/c kicks on. The fan motor was making some noise and when I hit the top of the unit blade rotated a revolution, hit it again and it started running, I equate this to passing the stick start test. System cools when running. Not sure but the fan may stop in the middle of cooling but may only stop when a/c goes off and comes back on. A/C company cant make it out for a few days and it seems like its the capacitor and I'm comfortable replacing that. just want conformation on whether the start cap needs to be replaced or the run cap. I believe the run cap is the large cylinder one with "50uf 6uf 440vac" on the side and three terminals, and the start cap is the oval cylinder with 2 terminals. Thanks for any input you guys can give.
 
Sponsored Links
  #2  
Old 06-26-14, 10:43 AM
Bob14525's Avatar
Member
Join Date: Jun 2013
Location: USA
Posts: 1,522
Received 20 Votes on 15 Posts
You're correct, the Start capacitor is the one that needs to be replaced. However, I can't tell you which one is which. If there is a wiring diagram inside the outside unit, it may show wire colors which may help you determine which is which.
 
  #3  
Old 06-26-14, 11:36 AM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 57,093
Received 840 Votes on 787 Posts
Welcome to the forums.

A make and model of the compressor unit would be helpful.
 
  #4  
Old 06-26-14, 12:27 PM
Houston204's Avatar
Forum Topic Moderator
Join Date: Oct 2009
Location: Texas
Posts: 7,426
Received 17 Votes on 14 Posts
The dual run cap requires replacement.
The start cap does not control the fan motor.
 
  #5  
Old 06-26-14, 03:40 PM
P
Member
Join Date: Jul 2009
Location: FL
Posts: 33
Received 0 Votes on 0 Posts
Considering the price of caps, I would replace both, if doing it myself.
 
  #6  
Old 06-27-14, 06:44 PM
P
Member
Thread Starter
Join Date: Jun 2014
Posts: 2
Received 0 Votes on 0 Posts
Update

So I purchased a 50mF/5mF 440 dual run cap to replace. Was confused when trying to install as the wiring diagram didn't match; no fan wire (purple) and 2 common (red). Upon further investigation the 2nd common (red) was jumping to another 5mF cap with my fan wire (purple) coming off. It seems this is a common way to fix cap issues to only replace the low cap for the fan motor? So I took out both caps and hooked up my new dual run cap connecting all three wires (F,C,H) according to wiring diagram. So far, so good. Just want a heads up if this sounds right to you guys.
 
  #7  
Old 06-27-14, 06:50 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 57,093
Received 840 Votes on 787 Posts
Many service guys just carry single capacitors and will just install what's actually needed.
I've always been a big fan of separate capacitors.

What you did sounds fine. If it works ok then you're all set.
 
  #8  
Old 06-27-14, 07:44 PM
Houston204's Avatar
Forum Topic Moderator
Join Date: Oct 2009
Location: Texas
Posts: 7,426
Received 17 Votes on 14 Posts
If I don't have a dual cap in the van but I can do the job with 2 caps and save the customer a trip charge for the parts house I install 2 caps instead of a dual cap. It does seem like separate caps swell up less often but they don't fit as well in many electrical compartments.

If a 45/5 x 440 dual cap reads 0 and 5, I can't install just a 45uF cap. I would worry that the other half will soon fail.
 
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: