Ice-O-Matic 16, Service And Installation Manual

Page: 78 / 164

ICE Series Electrical System
Page F5
Harvest Cycle
Single Evaporator Machines
Once the freeze timer has timed out, power is sent to relay 1 and the machine enters the harvest
cycle. Once in harvest motor, the purge valve, hot gas valve and harvest motor are energized.
The water pump continues to run during the first part of the harvest cycle so that mineral laden
water remaining in the water trough can be pumped through the purge valve to the drain. The
harvest motor turns the clutch assembly to actuate the cam switch.
The cam switch is in the normally closed position during freeze and at the beginning of harvest.
Once the clutch turns far enough to actuate the cam switch, the water pump and purge valve is de-
energized. The harvest motor continues to turn the clutch. When the cam switch returns to the
normally closed position, the machine returns to the freeze cycle.
If the bin switch is open when the cam switch is actuated by the high part of the cam, the machine
will shut off. Remote units pump down before shutting off.
Relay 1
When relay 1 is energized, the normally open contacts (1-B) close sending power to the hot gas
valve and harvest motor and (1-A) close sends power to the purge valve and the coil of relay 1 to
keep the coil energized when the timer initiate opens. The fan motor on self contained air cooled
model are wired through the NC contacts of relay 1, when the contacts open during harvest, the
condenser fan motor is de-energized.
Relay 2 See Page F4.
Dual Evaporator Machines
Once the freeze timer has counter out, power is sent to: (A) harvest motor 1 and relay coil 1
through the normally closed contacts of cam switch 1, (B) to harvest motor 2 and relay coil 2
through the normally closed contacts of cam switch 2. The contacts of relay 1B and 2B closing,
energizes the 4-second hot gas delay timer (Right Hand Timer)
This 4-second delay will allow the harvest motors to rotate and allow the cam switches to switch to
the normally open position before the low-pressure control opens during hot gas. The cam
switches are now in the normally open position and will continue to energize the harvest motors
and relays until the cam rotates and the switch returns to the normally closed position.
Once the 4-second delay timer has timed out, the hot gas valves and purge valve will energize
and allow hot gas into the evaporators. The bin control switches are by passed through the
normally open contacts of relay 1A and 2A.
The bin switches are bypassed to allow the cam switch to return to the normally closed position
prior to the machine shutting down if the curtain is open. Each harvest assist motor will only make
one revolution prior to shutting down on full bin or advancing to the next freeze cycle.
Both hot gas valves and the water purge valve remain energized until both harvest assist motors
complete one revolution. The water pump is energized throughout the harvest cycle. The unit will
shut down if the curtains are open during the freeze cycle. Remote units pump down before
shutting off. The fan motors on self contained air cooled model are wired through the NC contacts
of relay 1B, when the contacts open during harvest, the condenser fan motors are de-energized.