AC Compressor Not Working


  #1  
Old 06-07-12, 10:26 AM
J
Member
Thread Starter
Join Date: Jun 2012
Posts: 2
Upvotes: 0
Received 0 Upvotes on 0 Posts
Question AC Compressor Not Working

Turned on AC and only fan was working. I started reading the postings and began by checking the capacitor. Have a meter that can measure mF. It is a dual capacitor 5mF/ 80mF rating. I could measure 4.5mF on fan to C and OL on HERM to C. Assume that the cap is the problem so I replaced it. installed the new cap then measure got 5 mF on fan to C and OL on HERM to C. What's up with that? Also compressor still not working. What is my next step?
 
  #2  
Old 06-07-12, 02:40 PM
R
Member
Join Date: Apr 2011
Location: nj
Posts: 526
Upvotes: 0
Received 0 Upvotes on 0 Posts
thats pretty odd. what type of meter do you have? for example i used to have one that would do 0-10 on one scale and another setting for 10 and above. you obviously now how to check since your already half way there so no need to go over basics. the wires are off the cap when you test correct??
 
  #3  
Old 06-07-12, 03:28 PM
E
Member
Join Date: Feb 2010
Location: usa
Posts: 564
Upvotes: 0
Received 0 Upvotes on 0 Posts
80mf, dang thats alot. Next make sure the wires have not burnt or came off the compressor, you will have to take the top off to do so.
 
  #4  
Old 06-08-12, 06:24 AM
J
Member
Thread Starter
Join Date: Jun 2012
Posts: 2
Upvotes: 0
Received 0 Upvotes on 0 Posts
AC compressor not working

I went back and disconnected the wires to the cap and successfully measured 80 mF. put the wires on and inspected the contactor it a 2 pole and both sides engage. Metering across the load side I get 230V so I assume this is good. Is it time to call a professional? Or can I check something else? Thanks
 
  #5  
Old 06-08-12, 06:32 AM
Gunguy45's Avatar
Super Moderator
Join Date: Dec 2007
Location: USA
Posts: 19,281
Received 8 Upvotes on 8 Posts
You can check for a ground or open on the comp...but I can't tell you how. Might want to do a search or wait for a Pro to weigh in.
 
  #6  
Old 06-08-12, 10:19 AM
E
Member
Join Date: Feb 2010
Location: usa
Posts: 564
Upvotes: 0
Received 0 Upvotes on 0 Posts
And all the wires are on the compressor? Why can't you tell him how to check if the compressor has grounded itself?
 
  #7  
Old 06-08-12, 07:16 PM
R
Member
Join Date: Apr 2011
Location: nj
Posts: 526
Upvotes: 0
Received 0 Upvotes on 0 Posts
okay good. so you are measuring 80 mfd. and your contactor is pulling in, even better. you probably have an open compressor winding. shut down system, pull disconnect or shut off breaker. locate the 3 wires going to your compressor (remember where they go) take your meter and set it to ohms or tone function. now you will take 2 wires at a time. your 3 wires are start, run and common. basically test C to R, C to S and S to R. if its a one phase compressor your common to run plus your common to start should equal the same resistance as start to run. most likely you have an open winding. if this is the case, you should probably switch to 410A
 

Last edited by hvactechfw; 06-09-12 at 03:07 PM.
 

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