Hoshizaki DCM-270BAH Service Manual page 13

7) Refill Cycle/Low Water Safety – As ice is produced, the water level in the reservoir
drops. UFS opens. Nothing occurs at this time. When LFS opens, WV energizes,
90-sec. low water safety timer (fill timer) starts. Comp, GM, CDR, and FM continue.
When UFS closes, WV de-energizes, 90-sec. low water safety timer (fill timer)
terminates and 30-min. freeze timer resets. If UFS remains open 90 sec. after WV
energizes (fill timer exceeded), a 90-sec. shutdown cycle starts. Comp and FM
de-energize and CB signals a 1-beep alarm every 5 sec. 90-sec. ice purge timer
starts. GM and CDR continue to clear ice from the evaporator. 90-sec. purge timer
terminates, GM and CDR de-energize. WV and 1-beep alarm continue until UFS closes.
Diagnosis – Check that "WTRIN" LED is on. If not, check LFS. See "II.E. Float Switch
Check and Cleaning." If LFS is open and "WTRIN" LED is off, replace CB. If "WTRIN"
LED is on, check that the reservoir fills. If not, check the water supply line, restricted
water filters, WV solenoid, restricted WV screen. If WV is energized and refill exceeds
90-sec. low water safety timer (fill timer), check DV leaking by or open UFS.
See "II.E. Float Switch Check and Cleaning."
Note: Each time UFS closes, 30-min. freeze timer starts. The 30-min. freeze timer resets
when UFS closes again. If UFS does not close again within 30 min., CB shuts
down the unit and sounds a 5-beep alarm every 5 sec. See "II.B. LED Lights and
Alarm Safeties."
10) Shutdown – Bin fills with ice activating BC microswitch. Within 10 sec. control
board shutsdown unit. Diagnosis: Check that BC large balance plate is activated
and not sticking. Check BC microswitch continuity. When BC large balance plate is
down (icemaking), BC microswitch is closed. When BC large balance plate is up BC
microswitch is open. If not, replace BC microswitch. If BC microswitch is open and
Comp, FM, and GM do not de-energize, replace CB. See "II.C. Control Board Check
Procedure."
Legend: BC–bin control; CB–control board; CDR–compressor delay relay;
Comp–compressor; CT–control transformer; DV–drain valve; FM–fan motor;
GM–gear motor; LFS–lower float switch; UFS–upper float switch; WV–inlet water
valve
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