Refrigeration System Section 77-8 Part No. 80-1214-3ANALYZING SUCTION PRESSURENOTE: Analyze discharge pressure before analyzing suction pressure. High or low discharge pressure may becausing high or low suction pressure.Suction Pressure High ChecklistSuction Pressure Low ChecklistNOTE: Do not limit your diagnosis to only the items listed in the checklists.Possible Cause Check/CorrectImproper installation See “Installation/Visual Inspection Checklist”Discharge pressure Discharge pressure is too high, and is affecting suction pressure(See “Freeze Cycle Discharge Pressure High Checklist”Improper refrigerant charge OverchargedWrong type of refrigerantNon condensables in systemOther Non-Manitowoc components in systemTXV flooding (check bulb mounting)Defective compressorPossible Cause Check/CorrectImproper installation See “Installation/Visual Inspection Checklist”Discharge pressure Discharge pressure is too low, and is affecting suction pressure (See “Freeze CycleDischarge Pressure Low Checklist”)Improper refrigerant charge UnderchargedWrong type of refrigerantOther Non-Manitowoc components in systemRestricted/plugged liquid line drierRestricted/plugged tubing in suction side of refrigeration systemExpansion valve starvingNo water or insufficient pressureDefective compressorMoisture in refrigeration systemDirty EvaporatorDefective Fan Cycle ControlRFC2085/RFC2385 Only - Defe ctive Head Pressure ControlRevised 8/2003
