Service manual

36
Installation and Service Manual
COMPONENT DIAGNOSTICS
3 RELAY CIRCUIT BOARD SEQUENCE OF OPERATION /
ADJUSTING BRIDGE THICKNESS / 3 RELAY CIRCUIT BOARD
CUBES
BRIDGE 1/8"
(0.32 cm)
Adjusting Bridge Thickness
For optimum ice production and maximum cube
seperation, the ice connecting the individual cubes
should be a minimum of 1/8" (.32cm) thick at the center
of the ice waffle.
3 Relay Circuit Board
These five (5) steps must be followed in proper sequence:
1. Set fine "pot" to 50
2. Set coarse "pot" to 50
3. Allow cuber to build ice until bridge appears to
be correct thickness (1/8" to 3/16" (.32 to .49cm)
thick
4. With water curtain in place, slowly advance (to-
wards 100) coarse "pot" until harvest mode be-
gins - allow the ice to harvest and check bridge
thickness to be 1/8" to 3/16" (.32 to .49cm) thick.
5. Additional adjustments to be made with fine "pot"
turning 1/2 to 1 division at a time until 1/8" to 3/
16" (.32 to .49cm) bridge is achieved. The lower
the number, the thicker the bridge.
NOTE: Too thin of a bridge (less than 1/8" (.32cm)
will cause harvest problems.
NOTE: Never judge the thickness from the first batch
of ice produced - the first cycle is a machine
balance cycle. Always wait for the second
cycle before making any adjustments.
3 Relay Circuit Board Sequence Of Operation
When the toggle switch is placed in the ice mode,
the control board activates the water pump, condenser
fan motor (on air cooled units), the compressor contactor.
The water pump circulates the water supply across
the evaporator. The refrigeration system chills the evapo-
rator removing removing the heat from the water and ice
is formed. This process continues until the ice rolls over
the evaporator bottom extrusion covering the thermistor
sensing tip. At approximate 26
o
F (-3.3
o
C) ice tempera-
ture the thermistor signals to the control board to start
the harvest mode.
The control board shuts down the water pump, con-
denser fan (on air cooled units) and activates the hot
gas valve for the harvest mode. When the water pump
stops, the water in circulation returns the water pan in-
creasing the water level and creates the siphon action.
The siphon action cleans the water pan. The float as-
sembly allows fresh water to fill the water pan for the
next cycle.
With the hot gas valve open the evaporator warms
up to allow the ice to move off the evaporator. The ice
travle forces the water curtain to open. The opening of
the water curtain interrupts the proximity switch circuit,
closing the hot gas valve. The ice falls into the storage
bin, the curtain closes activating the proximity switch and
the next refrigeration cycle begins. This operation is re-
peated until the ice drop during harvest can not clear the
water curtain. The curtain being held open for approxi-
mately 15 seconds causes the proximity switch to indi-
cate a full bin, the curtain will close and the ice machine
will start in a refrigeration mode. The cycle(s) are re-
peated until the bin is once again full and the water cur-
tain opens allowing the proximity switch to shut down
the ice machine operation.