AC wont turn on


  #1  
Old 04-20-16, 10:45 PM
R
Member
Thread Starter
Join Date: Apr 2016
Location: USA
Posts: 4
Received 0 Votes on 0 Posts
AC wont turn on

I tried to turn on AC for the first time this summer and it didn't turn on. Air blower kicked in but the compressor didn't start. I search a little bit online and did some debugging myself. Here is what I found:
1. At disconnect switch, I do not see 240V between L1 and L2. I see 120V between L1 and GND and only 15V between L2 and GND. Between L1-L2 the multimeter reads only 75V or so.
2. Checked breaker and it was ON. I turned it OFF and then back ON with no luck.
3. I checked at breaker that there is 240V across 2 poles.


So I am wondering is it a faulty wire between breaker and disconnect switch? AC was working fine just before last winter. Will appreciate any helpful suggestions from folks here.
 
  #2  
Old 04-20-16, 11:20 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Jersey
Posts: 70,188
Received 2,982 Votes on 2,690 Posts
Welcome to the forums.

If you have 240v at the main panel but not at the disconnect.... you do have a problem.
It is rarely ever a defective cable. It would be more likely to be a loose connection.

When you checked for voltage at the disconnect.... were you checking the incoming line or the line to the condensor ? They both need 240v on them.
 
  #3  
Old 04-21-16, 04:39 AM
R
Member
Thread Starter
Join Date: Apr 2016
Location: USA
Posts: 4
Received 0 Votes on 0 Posts
I checked at incoming line to disconnect -- checked at exposed copper connected to connector. I didn't do the same at mainline -- perhaps it is a loose connection at mainline breaker. I will check it today.
 
  #4  
Old 04-21-16, 04:53 AM
Geochurchi's Avatar
Member
Join Date: Nov 2012
Posts: 5,585
Received 154 Votes on 140 Posts
Can you follow the feed from the breaker to the disconnect?is there a junction box any where in the line,not normal but possible.
 
  #5  
Old 04-21-16, 08:16 AM
R
Member
Thread Starter
Join Date: Apr 2016
Location: USA
Posts: 4
Received 0 Votes on 0 Posts
I noticed there is another disconnect switch along garage and away from AC. Perhaps it was for originally planned location for HVAC but later it was put in my backyard. Earlier I thought it was for dryer but then I checked that it is not. One of the fuse in this disconnect box is blown -- will replace it today and check if this fixes the AC.
 
  #6  
Old 04-21-16, 09:31 PM
R
Member
Thread Starter
Join Date: Apr 2016
Location: USA
Posts: 4
Received 0 Votes on 0 Posts
Replacing a fuse at 2nd disconnect box did the trick. It is working now. Thanks for your help!
 
  #7  
Old 04-21-16, 09:51 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Jersey
Posts: 70,188
Received 2,982 Votes on 2,690 Posts
Good find. Let the cold flow.
 
 

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