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HARVEST (DEFROST) CYCLE
REFRIGERATION SYSTEM SCHEMATIC
REFRIGERATION SYSTEM DURING HARVEST
The refrigeration system performs the harvest of
ice by use of a hot gas bypass valve. When the
time comes to de-ice the evaporators, the hot
gas valve is energized, and the high temperatu-
re, high pressure gas bypasses the condenser,
and is allowed directly into the evaporator. The
high pressure gas is cooled by the cold evaporator
so it condenses into a liquid, giving up its heat as
it does so. This heat warms the evaporator and
the ice frozen onto the evaporator surface melts,
releasing the frozen cubes. Ice then falls into the
storage bin pushed out by means of the harvest
assist solenoid.
The liquid refrigerant goes through the suction
line into the heat exchanger where it boils-off so
that only refrigerant vapor is drawn into the
suction tube of the compressor.
WATER SYSTEM
During the harvest cycle, the electric water
drain valve is energized thereby opening the
drain line.
Most of the water remained in the reservoir at the
end of freezing cycle is pumped-out, to the
waste, through the water solenoid and drain line
during the first part of the defrost cycle eliminating
any possible build-up and accumulation of
minerals concentration and impurities in the water
reservoir.
When the released ice cubes drop into the bin,
they open-up for a while the bottom end of plastic
deflector.
This deflector swinging motion is enough to reset
the contact of the magnetic switch which - via
electronic control board - moves back the unit to
a new freezing cycle.
The harvest cycle lasts about 1
÷
1.5 minutes.
CONTROL SEQUENCE
At the start of the freezing cycle, the contacts of
the magnetic switch mechanically operated by
the actuator plate of the deflector cover are
closed, thereby - via electronic control board -
closing the circuit to the main contactor coil and
