D&C A/C Services Provides quality Heating and Air Conditioning Service in San Antonio and Surrounding Areas

Defective Run CapacitorsDots

The compressor run capacitor in your central air conditioning unit has a very important job.  It helps start your compressor, and helps your compressor to run more efficiently.  Occasionally these parts can be worn down or rendered ineffective all together, for a variety of reasons.  Compressor manufacturers recommend replacing any capacitor which does not measure to have at least 90% of its rated value in microfarads.  Weak or open capacitors can cause undue stress on the compressor, and increased operating cost.  Below is an example of the increased operating expense in one cooling season in San Antonio for a 5-Ton unit operating with a defective compressor run capacitor.  Our technicians are equipped with digital capacitor analyzing meters to properly test your equipment.  If we have recommended replacement of one or more of your run capacitors it is because we want your system to be reliable and run efficiently.  All return trips for repairs recommended at the time of our first visit are subject to an additional return trip fee. 

5-Ton Compressor with Good Run Capacitor                       5-Ton Compressor with Bad Run Capacitor
                Voltage                                240 Volts                                               Voltage                                240 Volts
                Current                       x       18 Amps                                                                                    x        23 Amps
Total watts used          4320 per hour                                         Total watts used           5520 per hour

                Difference in watts/hr                                   =         1200
                Cooling hours/ yr in San Antonio                  x      2000
                Total additional watts used                          = 2,400,000 or 2400 kilowatts
                Cost for electricity in San Antonio .075 per kilowatt hour
                Total cost for additional watts used = $180.00     

                *Condenser fan motors and indoor blower motors also use run capacitors.  Power savings are less, because less current is used in these motors.  However, left unchecked the motor is still subject to overheating and probable failure.