Section 6 - Electrical System; Energized Parts Charts; Self-Contained Air- And Water-Cooled Models - Manitowoc J250 Service Manual

Section 6

Energized Parts Charts

SELF-CONTAINED AIR- AND WATER-COOLED MODELS

Ice Making
Sequence
Of
Operation
Start-Up
1
1. Water Purge
2. Refrigeration
System Start-Up
Freeze
Sequence
3. Pre-Chill
4. Freeze
Harvest
Sequence
5. Water Purge
6. Harvest
Automatic
7.
Shut-Off
1
Initial Start-Up or Start-Up After Automatic Shut-Off
Condenser Fan Motor
The fan motor is wired through a fan cycle pressure
control, therefore, it may cycle on and off.
Harvest Water Purge
New style circuit boards have an adjustable water
purge in the havest cycle. This permits a 0 (off), 15,
30 or 45 second purge cycle.
Auto Shut-Off
The ice machine remains off for 3 minutes before it
can automatically restart. The ice machine restarts
(steps 1-2) immediately after the delay period, if the
bin switch re-closes prior to 3 minutes.
Safety Timers
The control board has the following non-adjustable
safety timers:
Section 6 Electrical System
Control Board Relays
1 2 3
Water
Water Hot Gas
Dump
Pump Valve
Valve
On On On
Off On Off
Off Off Off
On Off Off
On On On
Off On Off
Off Off Off
Contactor
4 4A
Contactor
Compressor
Coil
Off Off
On On
On On
On On
On On
On On
Off Off
FREEZE SEQUENCE
• The ice machine is locked into the freeze cycle
for the first 6 minutes, not allowing the ice
thickness probe to initiate a harvest sequence.
• The maximum freeze time is 60 minutes, at which
time the control board automatically initiates a
harvest sequence (steps 5-6).
HARVEST SEQUENCE
• The maximum harvest time is 3-1/2 minutes, at
which time the control board automatically
terminates the harvest sequence. If the bin switch
is open, the ice machine will go to automatic
shut-off (step7). If the bin switch is closed, the ice
machine will go to the freeze sequence
(steps 3-4).
Electrical System
4B Length
Of
Condenser
Time
Fan Motor
Off 45 Seconds
May Cycle
5 Seconds
On/Off
May Cycle
30 Seconds
On/Off
Until 7 sec. water
May Cycle
contact with ice
On/Off
thickness probe
May Cycle Factory-set at
On/Off 45 Seconds
May Cycle Bin switch
On/Off activation
Until bin switch
Off
re-closes
6-1