ICE MACHINES Q-Model Service Manual

Refrigeration System Section 7DISCHARGE LINE TEMPERATURE ANALYSISGeneralKnowing if the discharge line temperature is increasing,decreasing or remaining constant can be an importantdiagnostic tool. Maximum compressor discharge linetemperature on a normally operating ice machinesteadily increases throughout the freeze cycle.Comparing the temperatures over several cycles willresult in a consistent maximum discharge linetemperature.Ambient air temperatures affect the maximum dischargeline temperature.Higher ambient air temperatures at the condenser =higher discharge line temperatures at the compressor.Lower ambient air temperatures at the condenser =lower discharge line temperatures at the compressor.Regardless of ambient temperature, the freeze cycledischarge line temperature will be higher than 160°F(71.1°C) on a normally operating ice machine.ProcedureConnect a temperature probe on the compressordischarge line with-in 6" of the compressor and insulate.Observe the discharge line temperature for the last threeminutes of the freeze cycle and record the maximumdischarge line temperature.Discharge Line Temperature Above 160°F (71.1°C) AtEnd Of Freeze Cycle:Ice machines that are operating normally will haveconsistent maximum discharge line temperatures above160°F (71.1°C).Discharge Line Temperature Below 160°F (71.1°C) AtEnd Of Freeze CycleIce machines that have a flooding expansion valve willhave a maximum discharge line temperature thatdecreases each cycle.Verify the expansion valve sensing bulb is 100%insulated and sealed airtight. Condenser air contactingan incorrectly insulated sensing bulb will causeoverfeeding of the expansion valve.Verify the expansion valve sensing bulb is positionedand secured correctly.7-22 Part No. 80-1100-3