• Fault 1: Open circuit in 12 volt supply to Trinary switch relay RL1 inactive. – Symptom Compressor clutch does not cut in
  • Fault 2: Open circuit in evaporator fan speed circuit causing the fan not to work on second speed Symptom: Second speed of evaporator fan not working
  • Fault 3: Short circuit causing evaporator fan to run
  • -Symptom: Evaporator fan will not switch off
  • Fault 4: Fault in temperature control circuit symptom compressor will not cut out once engaged Symptom: Temperature control only works in one position and then will not switch off causing pipe work to freeze back
  • Fault 5: Condenser fan will not operate, N.B. Trinary switch should cut compressor out between 24 26 bar. Symptom: Condenser fan not working causing an increase of pressure on the high side and the system is shut down by the Trinary switch overload.
  • Fault 6: Evaporator fan will not operate causing pipe work to freeze back.- Symptom: Evaporator fan not working causing low side to drop in pressure and temperature control not to operate correctly. Pipe work will also freeze back.
  • Fault: 7: Close shut off valve to simulate a blocked orifice in the expansion valve.- Symptom: Valve shut off simulating a blocked orifice, the low side pressure drops to zero and the compressor overloads.