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FAQ Answer


Error Code E4:


Compressor Overload:  this code means that one of the safety overloads on the compressor has activated.

Diagnosis:  the compressor has both an electrical and a temperature overload device built into it.  The thermal overload will trip if the gas temperature reaches 154.4° Fahrenheit.  This error can be reset by turning the unit off and on.  Try one of the following solutions:

  • High ambient temperature, with a low ambient kit installed, Unionaire systems will function up to 122° Fahrenheit.
  • Blockage in the refrigerant circle, make sure both service valves are fully open, a high pressure on the liquid side, over 350 psig, and a low suction side, under 40 psig, indicates a blocked cap tube.  If a blockage is diagnosed, the system must be evacuated, blown back and cleared.  It is recommended that a filter/dryer be installed in the vapor line before pumping down and recharging.
  • Condenser fan not working, if the compressor runs, but the fan does not, the motor or its capacitor may have failed.  Repair or replace as necessary.
  • Compressor problem, if the compressor has developed internal faults, it could simply be starving for oil.  Examine the installation of the unit to insure that the refrigerant lineset has been trapped properly to facilitate oil return.  Any other internal problem with the compressor will mean replacement is necessary.
  • Compressor wiring, if the compressor and/or its capacitor have been wired incorrectly, the compressor could overload.  Rewire as necessary.

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