A/C works until temps get high


  #1  
Old 08-17-11, 08:03 AM
F
Member
Thread Starter
Join Date: Apr 2009
Location: usa
Posts: 3
Upvotes: 0
Received 0 Upvotes on 0 Posts
A/C works until temps get high

Hi All

I have a 9 year old Goodman propane furnace and A/C located in the garage (compressor outside). We have never used the heat but with our northern California summers, use the A/C most days for about 3 months. The following problem began about 6 weeks ago: The A/C works fine for most of the day until the temperature in the garage, typically late in the day (5 to 6 p.m.), gets hot. At that point, when the thermostat calls for cooling, the furnace blower comes on but the compressor does not – no exhaust fan, no compressor.

I have had repairmen out 3 times and of course, the problem won’t replicate (the garage doesn’t get hot enough until normal work hours are just about over). They have checked relays, capacitor, voltages at the compressor, etc and everything is within specs. In frustration, I changed out the control board and cleaned the relay points but to no avail. Any thoughts on what might be happening?

Thanks
 
  #2  
Old 08-17-11, 08:34 AM
C
Member
Join Date: Aug 2008
Location: Texas, California
Posts: 1,411
Upvotes: 0
Received 7 Upvotes on 7 Posts
When condenser stops, Check the contactor to make sure it is pulled in, and you may want to check and replace the capacitor too.
 
  #3  
Old 08-17-11, 08:54 AM
F
Member
Thread Starter
Join Date: Apr 2009
Location: usa
Posts: 3
Upvotes: 0
Received 0 Upvotes on 0 Posts
Capacitor was checked twice by repairmen and both guys said the capacitance was at specs. Is it normal to have the capcitance read OK but fail under load?
 
  #4  
Old 08-17-11, 02:11 PM
E
Member
Join Date: Feb 2010
Location: usa
Posts: 564
Upvotes: 0
Received 0 Upvotes on 0 Posts
does it have a condensate pump? Could be filling with water and shutting ac down. Could be a dirty condenser that, in the heat of the day, causes the head pressure to rise and forces the unit to shut off. But if that were the case the small copper line to outdoor unit would be hot to the touch while running.
 
  #5  
Old 08-17-11, 02:11 PM
C
Member
Join Date: Aug 2008
Location: Texas, California
Posts: 1,411
Upvotes: 0
Received 7 Upvotes on 7 Posts
It is hard to say. To make sure, you need to use a multimeter to check the Volts on the fan and compressor terminals when they stop running.
 
  #6  
Old 08-17-11, 02:13 PM
Gunguy45's Avatar
Super Moderator
Join Date: Dec 2007
Location: USA
Posts: 19,281
Received 8 Upvotes on 8 Posts
No Pro...but I might wonder about the transformer? When heated, might be providing enough to run the stat and any relays for the blower...but not enough for the contactor?

As clocert said...need to check that and use a voltmeter to check voltage.
 
 

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