Hoshizaki MODULAR CUBELET SERENITY SERIES FS-1022MLH-C - Manual (Page 12)

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B. Sequence of Operation
The steps in the sequence are as outlined below. This unit utilizes a control board to
switch the icemaker components on and off as needed. When power is supplied, the
power switch is in the "ON" position, and the control switch is in the "ICE" position,
control board "POWER OK" LED and infrared sensor green LED come on. The "POWER
OK" LED remains on constantly. If the infrared sensor yellow LED is on or flashing, move
ice away from the infrared sensor lens.
This system utilizes a pump-down solenoid valve in the icemaker and a control
low-pressure switch in the condensing unit to control the operation of the Comp and
FMR. This eliminates the need for an electrical connection between the 2 units. When
calling for ice, the control board (X1 on control board) energizes the pump-down
solenoid. The low-side refrigerant pressure rises to 29 PSIG, the control low-pressure
switch (located in the condensing unit) closes, energizing the Comp and FMR. When the
ice level satisfies the infrared sensor bin control (bin full), the unit goes into the shutdown
cycle. The control board de-energizes the pump-down solenoid valve (X1 on CB). The
low-side refrigerant pressure drops (unit pumping down). When the low-side pressure
drops to 9 PSIG, the control low-pressure switch opens, de-energizing Comp and FMR.
Control Low-Pressure Switch Settings: Cut-Out: 9 PSIG. Differential: 20 PSIG.
Cut-In: 29 PSIG.
1. Sequence Cycles and Shutdown
a) Fill Cycle
"WTRIN" LED is on. WV energizes and fill cycle begins. 90-second low water safety
timer starts. When UF/S closes, WV de-energizes, and 90-second low water safety timer
resets. 30-second GM delay timer starts. If 90-second low water safety timer terminates
before UF/S closes, WV remains energized, and a 1-beep alarm sounds.
b) Ice Purge Cycle
"GM" LED is on. 30-second GM delay timer terminates. GMR (X2 on CB), GM, GMPR,
and EH energize. 5-minute ice purge timer starts: GM runs for 5 minutes to clear any
ice from the evaporator. To bypass, press the "SERVICE" button on CB after GM starts.
WARNING! Risk of electric shock. Care should be taken not to touch live terminals.
Note: UF/S must be closed before GMR will energize.
c) Freeze Cycle
"COMP" and "GM" LEDs are on. 5-minute ice purge timer terminates. GMR (X2 on
CB), GM, GMPR, and EH continue. CR (X1 on CB) and PDS energize. When CLPS (in
SRC) closes, MC energizes, allowing Comp and FMR to energize. CCH de-energizes.
As water in the evaporator cools, ice starts forming within 4 to 6 minutes. This time frame
depends on the inlet water and ambient temperature conditions. UF/S and LF/S operate
WV as needed to continue the ice making process. This continues until IS activates
allowing CB to de-energize X1 on CB and PDS. The unit goes into pump-down, CLPS
opens, MC de-energizes, de-energizing Comp and FMR. CCH energizes.