Ice Making Sequence Of Operation - Pku0155; Freeze Sequence; Harvest Sequence - Motak PKU0155SA Manual De Instrucciones

Ice Machine Operation

Ice Making Sequence of Operation - PKU0155

The toggle switch must be in the ICE position and the ice damper must be closed before
the ice machine will start.
1. Pressure Equalization
Before the compressor starts, the harvest valve is energized for 15 seconds to equalize
pressures during the initial refrigeration system start-up.
2. Refrigeration System Start-up
The compressor starts after the 15-second pressure equalization, and remains on
throughout the entire Freeze and Harvest Sequences. The harvest valve 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 relay. As a result, any time the
relay 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 starts 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 time
has been surpassed.

HARVEST SEQUENCE

5. Harvest
The water pump de-energizes, stopping flow over the evaporator. The rising level of
water in the sump trough diverts water out of the overflow tube, purging excess minerals
from the sump trough. The harvest valve also opens to divert hot refrigerant gas into the
evaporator.
The refrigerant gas warms the evaporator, causing the cubes to slide, as a sheet, off the
evaporator and into the storage bin. The sliding sheet of cubes contacts the ice damper,
opening the bin switch.
The momentary opening and re-closing of the bin switch terminates the Harvest Sequence
and returns the ice machine to the Freeze Sequence (steps 3 - 4).
26 Part Number: 000016426 Rev 00 08/2020
Section 2