Ice-O-Matic ICE0250 Series - Manual (Page 79)

ICE Series Electrical System
Page F6
Harvest Assist Assembly
The harvest assist assembly
has several purposes: to assist
in moving the ice off of the
evaporator, to control the
length of harvest and to
terminate harvest. When the
machine enters harvest, power
is sent to the harvest motor
which turns a slip clutch. A
probe is attached to the
rotating clutch and is pushed
against the back of the ice
slab. The clutch begins to slip
when the probe applies
approximately 25 ounces of
pressure against the ice slab.
It takes approximately 1 minute
for hot gas to heat the evaporator enough to loosen the ice from the evaporator plate. At this point
the clutch pressure overcomes the capillary attraction of the ice to the evaporator plate and the ice
begins to move off of the evaporator. As the ice is being pushed, the clutch stops slipping and
begins to turn, extending the probe enough to push the ice completely off of the evaporator.
Harvest Motor
The harvest motor is energized at the beginning of harvest and will remain energized until the
machine returns to the freeze cycle. A defective harvest motor will usually not run. The harvest
motor rotates in a clockwise direction. It is possible for a defective motor to run backwards
(counterclockwise). If this happens the motor must be replaced. It is also possible for a defective
motor to “bump” backwards immediately when entering harvest. This will activate the cam switch
and cause the machine to return to the freeze cycle immediately after entering harvest. If the
machine is in harvest only for a split second, the harvest motor may be defective. Verify the motor
is defective by watching the clutch closely when the machine enters harvest.
Clutch Assembly
The clutch assembly consists of a slip clutch and cam. A probe is attached to the clutch assembly
and the harvest motor turns the clutch during harvest. As the harvest motor turns, the clutch will
slip while the probe is pushed against the ice. The clutch will continue to slip as long as the
pressure required to move the ice is greater than the 25 oz. Once the evaporator has heated
enough to break the bond of ice to the evaporator, the pressure required to move the ice becomes
less than the 25 oz. And the clutch begins to move.
The clutch assembly is not adjustable. If the clutch tension is weak (less than 25 oz.) a slow
harvest or excessive ice meltage during harvest will result. If the clutch pressure becomes too
tight, the force of the probe against the back of the ice may cause the slab to break and the ice
may not fall off of the evaporator. If the clutch tension is suspected of being too tight or loose, turn
the clutch by hand. The clutch should turn smoothly without “grabbing”, but should offer some
resistance. If in doubt as to whether or not the clutch is defective, compare the tension with one
that is known to be good.