Section 4 Ice Machine Sequence of Operation
4-1
Section 4 Basic Ice Machine Sequence of Operation
Self-Contained Air- and Water-Cooled
J200/J250/J320/J420/J450/J600/J800/J1000/J1300/J1800
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
completely purge the ice machine of old water. This
feature ensures that the ice making cycle starts with
fresh water.
The hot gas valve(s) is also energized during water
purge, although it stays on for an additional 5 seconds
(50 seconds 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 hot gas valve(s) remains
on for 5 seconds during initial compressor start-up
and then shuts off.
At the same time the compressor starts, the fan
condenser 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.)
FREEZE SEQUENCE
3. Prechill
The compressor is on for 30 seconds prior to water
flow, to prechill the evaporator.
4. Freeze
The water pump restarts after the 30 second prechill.
An even flow of water is directed across the
evaporator and into each cube cell, where it freezes.
When sufficient ice has formed, the water flow (not
the ice) contacts the ice thickness probe. After
approximately 7 seconds of continual water contact,
the harvest sequence is initiated. The ice machine
cannot initiate a harvest sequence until a 6 minute
freeze lock has been surpassed.
Freeze Sequence (Typical J450 Shown)
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