Manitowoc

Other• Non-Manitowoc components in system• Improper water supply over evaporator refer to“Water System Checklist” on page 105.• Loss of heat transfer from tubing on back side ofevaporator• Restricted/plugged liquid line drier• Restricted/plugged tubing in suction side ofrefrigeration systemNOTE: Do not limit your diagnosis to only the itemslisted in the checklists.HOT GAS VALVEGeneralThe hot gas valve is an electrically operated valve thatopens when energized, and closes when deenergized.Normal OperationThe valve is de-energized (closed) during the freezecycle and energized (open) during the harvest cycle.The valve is positioned between the receiver and theevaporator and performs two functions:1. Prevents refrigerant from entering the evaporatorduring the freeze cycle.The hot gas valve is not used during the freezecycle. The hot gas valve is de-energized (closed)preventing refrigerant flow from the receiver intothe evaporator.2. Allows refrigerant vapor to enter the evaporator inthe harvest cycle.During the harvest cycle, the hot gas valve isenergized (open) allowing refrigerant gas from thedischarge line of the compressor to flow into theevaporator. The heat is absorbed by theevaporator and allows release of the ice slab.Exact pressures vary according to ambienttemperature. Harvest pressures can be found in the“Cycle Time/24 Hour Ice Production/RefrigerantPressure Charts” in this book.154 Part Number 80-01111-9 7/10