Hoshizaki DCM 300BAH(-OS) service manual

12)Drain Cycle – "FLUSH" (drain) LED is on. The icemaker drains the evaporator and reservoir once every 12 hr. A manual drain is provided when cleaning the icemaker by moving the control switch from the "ICE" position to the "DRAIN" position.

a)Automatic Drain Cycle: A drain cycle occurs once every 12 hr. for 20 min.

DCT terminates and DVT starts. If the icemaker is not running when DCT terminates, DV energizes immediately. If the icemaker is running when DCT terminates, Comp and FM de-energize. GM de‑energizes 60 sec. later, then DV energizes. Once

DVT terminates, DCT resets and DV de‑energizes. Fill cycle starts. DCT resets every time the power supply is turned off and on again. Diagnosis: Once GM de‑energizes, DV energizes. If not, check for 24VAC at the control switch (LBU wire) to a neutral (LBU wire). If 24VAC is not present, replace CB. If 24VAC is present, check for 24VAC at GMPR terminal #2 (P wire) to a neutral (LBU wire). If 24VAC is not present, GMPR is energized or defective. If GMPR is energized, confirm GM is off. If not, DCT has not terminated or 60-sec. shutdown sequence is not complete. If 60‑sec. shutdown is complete and GM is still energized, replace CB. If 24VAC is present, check for 24VAC on DV. If 24VAC is present and DV does not energize,

check DV solenoid continuity.

b1) Manual Drain: 150-sec. shutdown sequence: Move the control switch to the "DRAIN" position. The 150-sec. shutdown sequence starts. 90 sec. after moving the control switch to the "DRAIN" position, Comp and FM de-energize, 60 sec. later GM de‑energizes and DV energizes. DV continues until the control switch is moved to the "OFF" or "ICE" position or power is turned off. Diagnosis: Once GM de‑energizes, DV energizes. If not, check for 24VAC at CB K3 connector pin #3 (DBU wire) to a neutral (LBU wire). If 24VAC is not present, confirm 24VAC power supply to CB K2 connector pin #7 (R wire) on push button model and pin #9 (R wire) on Opti‑Serve model to a neutral (LBU wire). If 24VAC is present on CB K2 pin #7 (push button model) or pin #9 (Opti‑Serve model) and not on CB K3 connector pin #3 (DBU wire), replace CB. If 24VAC is present at CB K3 connector pin #3 (DBU wire), check for 24VAC at control switch (LBU wire) to a neutral (LBU wire). If 24VAC is not present, check continuity of the control switch. Replace the control switch if defective. If 24VAC is not present, GMPR is energized or defective. If 24VAC is present, check for 24VAC at GMPR terminal #2 (P wire) to a neutral (LBU wire). If 24VAC is not present, check GMPR continuity between terminals #2 (P wire) and #6 (LBU wire). If open, replace GMPR. Next, check for 24VAC at DV. If 24VAC is present and DV does not energize, check DV solenoid continuity.

b2) Manual Drain: 150-sec. shutdown sequence bypass: To bypass the 150-sec. shutdown sequence, remove the front panel, then move the power switch to the "OFF" position. Next, move the control switch to the "DRAIN" position, then move the power switch to the "ON" position. DV energizes. IMPORTANT! Drain valve will not energize unless the front panel safety switch is engaged. Diagnosis: If DV does not energize, check for 24VAC at CB K3 connector pin

#3 (DBU wire) to a neutral (LBU wire). If 24VAC is not present, confirm 24VAC power supply to CB K2 connector pin #7 (R wire) on push button model and pin #9 (R wire) on Opti-Serve model to a neutral (LBU wire). If 24VAC is present at CB K2 pin

#7 (push button model) or pin #9 (Opti‑Serve model) and not on CB K3 connector pin #3 (DBU wire), replace CB. If 24VAC is present at CB K3 connector pin #3 (DBU wire), check for 24VAC at control switch (LBU wire) to a neutral (LBU wire). If 24VAC is not present, check continuity of the control switch. Replace the control switch

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