Qm20/Qm30; Initial Start-Up Or Start-Up After Automatic Shut-Off; Freeze Sequence - Manitowoc QM20 Technician's Handbook

QM20/QM30

INITIAL START-UP OR START-UP AFTER
AUTOMATIC SHUT-OFF
1. Water Purge
The water fill valve and the hot gas valve are
energized for 2.9 minutes (175 seconds). This ensures
that the ice making cycle starts with fresh water, and
that the refrigerant pressures are equalized prior to
refrigeration system start-up.
2. Refrigeration System Start-up
The compressor starts 2.9 minutes (175 seconds)
after the water fill valve and hot gas valve are
energized. (The water fill valve and hot gas valve
remain energized for 5 seconds during compressor
start-up, and then shut off.) The compressor remains
on throughout the entire freeze and harvest cycles.

FREEZE SEQUENCE

3. Freeze Cycle
The condenser fan motor and water pump are
energized and remain on throughout the entire freeze
cycle. An even flow of water is directed across the
evaporator and into each cube cell, where it freezes.
The control system automatically determines the
length of the freeze cycle by monitoring the
temperature of the refrigeration system liquid line.
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