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How to replace a burned-out air conditioning compressor AirCondAPedia © How to replace a burned-out air conditioning compressor Air conditioner compressor defect diagnosis

This chapter of "How to Inspect the Central Air Conditioning or Cooling System" discusses the how to replace a burned out air conditioner compressor. Contact us to suggest text changes and additions and, if you wish, to receive online listing and credit for that contribution.

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What is Involved in Air Conditioner Compressor Replacement

Replacing an air conditioner compressor is a job for a trained service technician. Not only is the compressor motor often the most costly part in the system, but it is not a simple "bolt-in" replacement. The service technician will:

• Confirm that the compressor has failed and needs replacement
• Identify the compressor model and capacity so that a proper replacement can be obtained
• Shut down the air conditioning system, including turning off electrical power
• Remove all refrigerant from the system. Modern procedures require that the refrigerant be captured rather than released to the environment in order to reduce environmental pollutants
• If the air conditioner system used a now-obsolete refrigerant such as R11 or R22, a the new compressor will be one designed to use a new, approved refrigerant and other changes may be needed to the system to accommodate this change, such as changes in thermal-expansion valves, coils, or other components. Not all components need replacement, however; ducts and blower assemblies, for example, are retained.
• The refrigerant lines are cut and the old compressor is removed.
• The new compressor is installed in place in the compressor/condenser unit (usually all of this equipment is located outside), and its refrigerant lines are connected (usually silver soldering) to the existing refrigerant lines. New coils or other controls may need to be cut out and replaced if the refrigerant is being changed too.
• A vacuum is pulled on the entire system both to evacuate all air from the refrigerant lines and compressor and to check for leaks in the system. Air contamination, if allowed to mix with the new refrigerant would change its operating characteristics and would prevent proper operation. Any water or moisture in the system is also removed and the technician may install a drier in the system to remove any trace moisture that remains behind after reassembly.
• Refrigerant is added to the system at the proper charge amount. Residential air conditioner systems, unlike commercial units, use a hermetically sealed compressor motor and there is no separate receiver to hold a large refrigerant charge, so the charge must be measured precisely (including temperature, pressure, and volume during charging) for the system to work properly. Both overcharging and under-charging refrigerants will lead to improper system operation.
• The air conditioning system, with its new compressor installed, will be re-started and checked for proper operation

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AIR CONDITIONING SYSTEMS
AIR CONDITIONER BTU CHART
AIR CONDITIONER COMPONENT PARTS
AIR CONDITIONER TYPES, ENERGY SOURCES
AIR CONDITIONER NOT WORKING
AIR FILTERS for HVAC SYSTEMS
AIR HANDLER UNIT
BOOKSTORE - Air Conditioning "How To" Books
CLEANING & Legionella BACTERIA
COMPRESSOR & CONDENSING COIL
  BURNED-OUT COMPRESSOR
  CAPACITORS for HARD STARTING MOTORS
  CONDENSING COIL FINS, SUPPORT PADS
  HARD STARTING COMPRESSOR MOTORS
  INSTALLATION ERRORS, COMPRESSORS
  MOTOR OVERLOAD RESET SWITCH
  NOISY COMPRESSOR UNITS
  PRESSURE READINGS, COMPRESSOR
  REPLACING A COMPRESSOR
  TIGHT or SEIZED AC COMPRESSORS
CONDENSATE HANDLING
CONTROLS & SWITCHES
COOL OFF HEAT Thermostat Switch
COOLING CAPACITY, RATED
COOLING COIL or EVAPORATOR COIL
DATA TAGS on AIR CONDITIONERS
COMBUSTION GASES & PARTICLE HAZARDS
COMBUSTION PRODUCTS & IAQ
DEFINITION of Heating & Cooling Terms
DEW POINT TABLE - CONDENSATION POINT GUIDE
DUCT SYSTEMS
DUCTS - Asbestos
DUCT SYSTEM DEFECTS
DUCT INSULATION, Asbestos Paper
DUCT INSULATION for SOUNDPROOFING
DUCTS, Asbestos Transite Pipe
DUST FROM HVAC?
FAN AUTO ON Thermostat Switch
HEAT LOSS (or GAIN) in BUILDINGS
HUMIDITY LEVEL TARGET
INSPECTION CHECKLIST - OUTDOOR UNIT
INSPECTION LIMITATIONS
LOST COOLING CAPACITY
  What to check first
  Compressor failure diagnosis
  Duct & Air Handler diagnosis
MOTOR OVERLOAD RESET SWITCH
OPERATING COST
OPERATING DEFECTS
OPERATING TEMPERATURES
  Air Conditioning System Temperatures
  Instruments Used to Measure A/C Temperatures
  Procedures for Making Temperature Measurements
REPAIR GUIDE for AIR CONDITIONERS
REPAIR & DIAGNOSTIC FAQs for A/C
REFRIGERANTS
SEER RATINGS & OTHER DEFINITIONS
SYSTEM OPERATION
THERMOSTATS
THERMOSTATIC EXPANSION VALVES
CRITICAL DEFECTS
Air Conditioning "How To" Books

• Thanks to Mark Cramer, Tampa Florida, for assistance in technical review of the "Critical Defects" section and for the photograph of the deteriorating gray Owens Corning flex duct in a hot attic. Mr. Cramer is a Florida home inspector and home inspection educator. Thanks to Jon Bolton, an ASHI, FABI, and otherwise certified Florida home inspector who provided photos of failing Goodman gray flex duct in a hot attic.
• Carson Dunlop, Associates, Toronto, have provided us with (and we recommend) Carson Dunlop Weldon & Associates' Technical Reference Guide to manufacturer's model and serial number information for heating and cooling equipment ($69.00 U.S.)
  

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