7)Startup–"POWER OK" LED is on: Move the power switch to the "ON" position, then move the control switch to the "ICE" position. CB "POWER OK" LED is on. "POWER OK" LED Diagnosis: Check that CB "POWER" LED is on. If not, check for proper power supply voltage (115VAC) input to CT. If 115VAC is not present, check the breaker, power switch, and safety switch. Next, check that the power protect relay is deenergized and contacts between terminals #6 (BR) and #2 (BK) are closed. Check for proper control voltage (24VAC) output from CT. Next, check the 24VAC 1A fuse. If open, replace. Check for 24VAC at CB K8 connector pin #1 (W/R) to CB K8 connector pin #2 (LBU). If 24VAC is not present at CB K8 connector pin #1 (W/R) but is present at 1A fuse (W/R), check continuity of control switch. If open, replace. If 24VAC is present between CB K8 connector pin #1 (W/R) and pin #2 (LBU), and "POWER OK" LED is off, replace CB.

BC Diagnosis: Check that the actuator paddle is properly positioned. Check for continuity across BC proximity switch. When BC proximity switch is closed 0VDC is read across CB K8 connector pin #3 (GY) and #4 (GY). 5VDC is present between CB K8 connector pin #3 (GY) or #4 (GY) to CB red K4 connector pin closest to CB black K3 black connector (5VDC GND). If 5VDC is not present, replace CB.

HPS Diagnosis: HPS automatically resets when refrigeration circuit high-side pressure is within an acceptable range. 5VDC is supplied from CB K9 connector pin #3 (Y) and back onto CB K9 connector pin #4 (Y). If 5VDC is not present at CB K9 connector pin #3 (Y) to CB red K4 connector pin closest to CB black K3 connector (5VDC GND) and CB "POWER OK" LED is on, replace CB. If refrigerant pressures have returned to an acceptable range and HPS does not close, replace HPS. If pressures have not equalized, and refrigeration circuit high-side pressure does not drop, recover, evacuate, and recharge if necessary. On air-cooled model, check that the condenser is not dirty or clogged, check for proper FM operation and fan blade for binding. On water-cooled model, check WRV and water flow in and out of condenser. Check for refrigeration circuit refrigerant restriction (TXV and drier).

8)Fill Cycle"WTRIN" LED is on: WV energizes. 90-sec. FT starts. LFS closes. Nothing happens at this time. Reservoir continues to fill. UFS closes, WV deenergizes, 90sec. FT terminates. Diagnosis: If the reservoir is empty, LFS open, "WTRIN" LED on, and WV off, check for 24VAC at CB K2 connector pin #8 (W/BR) to a neutral (LBU).

If 24VAC is not present, confirm 24VAC power supply at CB K2 connector pin #7 (W/R) to a neutral (LBU). If 24VAC is not present on CB K2 connector pin #7 (W/R), check wiring connections from CT. If 24VAC is present on CB K2 connector pin #7 (W/R) and not on CB K2 connector pin #8 (W/BR), replace CB. If 24VAC is present on CB K2 connector pin #8 (W/BR), check for 24VAC at WV solenoid. If 24VAC is present, replace WV. If WV is energized and fill/refill exceeds 90sec. FT with no water in the reservoir, check for clogged WV screen or DV leaking. Note: If UFS remains open

90 seconds after LFS opens (WV energized), a 1beep alarm sounds (90 sec. FT). This alarm resets automatically once UFS closes. If reservoir is full and overflowing, check for open UFS. See "II.E. Float Switch Check and Cleaning." If WV deenergizes and water continues to fill the reservoir, replace WV.

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Hoshizaki dcm-75ibah service manual