Service Manual

21
12) Shutdown
a) BC1 (infrared sensor): When power is supplied to the icemaker, the green LED on
BC1 turns on. The green LED remains on constantly. As ice lls the storage bin to the
level of activating BC1, BC1 yellow LED turns on (ashing or steady). The yellow LED
ashes when ice is at the outer limit of its range and turns steady as ice nears. After
the yellow LED turns on (ashing or steady), BC1 shutdown delay timer (S1 dip switch
1, 2, 3) starts. For a typical dispenser unit application, a 100-sec. shutdown delay is
recommended. When used with a standard Hoshizaki storage bin, any shutdown delay
setting is acceptable. See "III.B.2. BC1 (Infrared Sensor) Shutdown Delay (S1 dip
switch 1, 2, 3)." Once BC1 shutdown delay timer terminates, PDS de-energizes and the
5-min. ice purge timer starts. Unit is in pump-down mode. When the refrigerant low-side
pressure drops to 9PSIG, CLPS opens, MC de-energizes, de-energizing Comp and
FMR. CCH energizes. When the 5-min. ice purge timer terminates, GM, EH, CCR
de-energize.
Icemaker Diagnosis: BC1 yellow LED not ashing or on with ice near. See "II.D. Bin
Control Check." PDS remains energized after BC1 shutdown delay timer terminates.
Check for 115VAC from CB X1 relay (DBU) wire to neutral (W). If 115VAC is present,
replace CB. If 115VAC is not present, check PDS for mechanical failure.
Condensing Unit Diagnosis: When PDS de-energizes and closes, pump-down starts.
Conrm refrigerant low-pressure drops to 9PSIG and CLPS opens. If refrigerant
low-pressure reaches 9 PSIG and CLPS does not open, replace CLPS. If Comp and
FMR remain energized after CLPS opens, replace MC.
Note: If IS fails to shut down the icemaker, MBC opens, CB shuts down the icemaker
and sounds a 9-beep alarm.
b) BC2 (mechanical backup bin control): MBC opens (spout cover disengaged). CB
shuts down the icemaker within 10 seconds and sounds a 9-beep alarm.
Diagnosis: See "II.D.Bin Control Check."
Legend: BC1–bin control 1 (infrared sensor); BC2–bin control 2 (mechanical backup);
CB–control board; CCH–crankcase heater; CCR–compressor control relay;
CLPS–control low-pressure switch; Comp–compressor; CT–control transformer;
DV–drain valve; EH–evaporator heater; FMR–fan motor-remote;
FT–90-sec. low water safety timer; FZT–30-min. freeze safety timer; GM–gear
motor; HM–headmaster (C.P.R.); HPS–high-pressure switch; LFS–lower oat
switch; MC–magnetic contactor; PDS–pump-down solenoid valve; SLPS–safety
low-pressure switch; UFS–upper oat switch; WV–inlet water valve