AC Condenser Not Coming ON!!!

Reply

  #1  
Old 07-30-14, 06:32 PM
Member
Thread Starter
Join Date: Jul 2014
Location: USA
Posts: 5
Received 0 Votes on 0 Posts
AC Condenser Not Coming ON!!!

This morning I notice my house was getting warmer. I noticed my condenser was not running but my furnace fan was. Within the last year I have changed the compacitor, the contactor, thermostat and 3V fuse on control panel in the furnace. Here is what I have done so far.
  • Checked the breakers
  • Contactor is getting 240 volts
  • Pushed in the bar on the Condenser and it starts with no issues
  • Opened panel on furnance to ensure no trouble code on the control panel
  • Confirmed the 24V wire from the furnace is not broken by completing OHM test.
I am looking for suggestions on what next to troubleshoot.
Thanks.
 
Sponsored Links
  #2  
Old 07-30-14, 11:13 PM
Houston204's Avatar
Forum Topic Moderator
Join Date: Oct 2009
Location: Texas
Posts: 7,372
Received 10 Votes on 8 Posts
Measure for 24 volts at the 2 field installed wire nuts in the outdoor unit.
If you have 24 volts then check the contactor coil for 24 volts.

If the first test did not measure at least 24 volts AC then check for water in the pan under the indoor coil, check for 24 volts between Y and C at the furnace with the door switch pushed in and after waiting for the five minute timer to allow the 24 volt signal from the stat to the condenser to expire.
 
  #3  
Old 07-31-14, 07:08 PM
Member
Thread Starter
Join Date: Jul 2014
Location: USA
Posts: 5
Received 0 Votes on 0 Posts
There is 27 volts inside the furnance. Outside there was no voltage reading.
 
  #4  
Old 07-31-14, 07:15 PM
Houston204's Avatar
Forum Topic Moderator
Join Date: Oct 2009
Location: Texas
Posts: 7,372
Received 10 Votes on 8 Posts
What 2 terminals are you measuring in the furnace?
 
  #5  
Old 07-31-14, 08:35 PM
Member
Thread Starter
Join Date: Jul 2014
Location: USA
Posts: 5
Received 0 Votes on 0 Posts
I measured the Y and C terminals. I also got a new piece of wire and tried to replace teh wire to the condenser and still there was not 24volts on the end that wire either
 
  #6  
Old 07-31-14, 09:34 PM
Houston204's Avatar
Forum Topic Moderator
Join Date: Oct 2009
Location: Texas
Posts: 7,372
Received 10 Votes on 8 Posts
Many people make the mistake of only measuring for 24 volts at the contactor. This does not consider the pressure switches or time delay relay if present.
Where did you measure for 24 volts outside?

Many units have a float switch mounted on the pan under the evaporator coil. This float switch can be wired to interrupt the 24 volt signal to the outdoor unit when the pan fills with water.
 
  #7  
Old 07-31-14, 09:46 PM
Member
Thread Starter
Join Date: Jul 2014
Location: USA
Posts: 5
Received 0 Votes on 0 Posts
I checked the voltage at the wire coming into the condenser.
 
  #8  
Old 08-01-14, 04:59 AM
Bob14525's Avatar
Member
Join Date: Jun 2013
Location: USA
Posts: 1,470
Received 11 Votes on 8 Posts
Try unhooking the wires where they come into the condenser unit and measure the voltage across the wires coming from the house. Do you now read 24VAC when the thermostat is calling for cooling? If so, then something in the condenser unit is likely loading down the circuit. Using an ohmmeter, check the resistance across the wires inside the condenser unit (while they are still unhooked from the wire coming from the house.
 
  #9  
Old 08-01-14, 05:34 AM
Member
Thread Starter
Join Date: Jul 2014
Location: USA
Posts: 5
Received 0 Votes on 0 Posts
This is how I was checking and I do not have 24V from the wires coming from the house.
 
  #10  
Old 08-01-14, 06:57 AM
Bob14525's Avatar
Member
Join Date: Jun 2013
Location: USA
Posts: 1,470
Received 11 Votes on 8 Posts
I understood you to say that you had 24VAC between the Y & C terminals at the furnace, and you ran a new wire to the outside unit. Unless your new wire is bad, you should have 24VAC at the outside unit if you have it at the house side of the wire. That's why I was questioning whether something in the outside unit was "loading" the control line (when connected).
 
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
Display Modes
 
Ask a Question
Question Title:
Description:
Your question will be posted in: