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Below is a logical thought pattern to solve some electrical problems with a air conditioning. It is not designed to cover all problems encountered but creates a path to enhance the thoughts to resolving the problem. This chart is for use by certified technicians only.

Unit Running
       
    Yes
No  
  Go to Mechanical
Thermostat Problem    checks
       
   
Yes No  
Repair & Recheck  
Voltage on compressor
side of contactor
 
 
                     
   
Yes No
Run capacitor Voltage on line side of contactor
Start capacitor  
Potential relay            
Compressor internal overload open No Yes
Compressor winding open Check breakers or fuses Compressor contactor failure
Unit wiring connections loose   High pressure switch open
or miswired Yes low presure switch open
  Compressor time delay failed
Compressor winding grounded or not timed out yet
Outdoor fan motor grounded Miswired or loose connections
Grounded capacitor
Shorted line voltage wire
Miswired
 
Reset breaker or replace fuses
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