Manitowoc Marine Q 1000, Service Technician'S Handbook

Page: 23 / 179

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Ice Making Sequence of Operation
SELF-CONTAINED AIR- AND WATER-COOLED
Initial Start-Up or Start-Up After
Automatic Shut-Off
1. Water Purge
Before the compressor starts, the water pump and
water dump solenoid are energized for 45 seconds to
purge the ice machine of old water. This ensures that
the ice-making cycle starts with fresh water.
The harvest valve(s) is also energized during the
water purge, although it stays on for an additional 5
seconds (50-second total on time) during the initial
refrigeration system start-up.
2. Refrigeration System Start-Up
The compressor starts after the 45 second water
purge, and it remains on throughout the entire Freeze
and Harvest Sequences. The water fill valve is
energized at the same time as the compressor. It
remains on until the water level sensor closes for 3
continuous seconds, or until a six-minute time period
has expired. The harvest valve(s) remains on for 5
seconds during initial compressor start-up and then
shuts off.
At the same time the compressor starts, the
condenser fan motor (air-cooled models) is supplied
with power throughout the entire Freeze and Harvest
Sequences. The fan motor is wired through a fan cycle
pressure control, therefore it may cycle on and off.
(The compressor and condenser fan motor are wired
through the contactor. As a result, anytime the
contactor coil is energized, the compressor and fan
motor are supplied with power.)