Hoshizaki KM-1301SWH-E, KM-1301SRH-E, KM-1301SAH-E IV. Service Diagnosis, Diagnostic Procedure

IV. Service Diagnosis

WARNING

1.This unit should be diagnosed and repaired only by qualified service personnel to reduce the risk of death, electric shock, serious injury, or fire.

2.Risk of electric shock. Use extreme caution and exercise safe electrical practices.

3.Moving parts (e.g., fan blade) can crush and cut. Keep hands clear.

4.CHOKING HAZARD: Ensure all components, fasteners, and thumbscrews are securely in place after the unit is serviced. Make sure that none have fallen into the storage bin.

5.Make sure all food zones in the icemaker and storage bin are clean after the unit is serviced. For cleaning procedures, see "VI. Cleaning and Maintenance."

A. Diagnostic Procedure

The diagnostic procedure is basically a sequence check which can be used at unit startup or for system diagnosis. This procedure allows you to diagnose electrical system and component failures in normal operating conditions of 70°F (21°C) or warmer air and 50°F (10°C) or warmer water temperatures. Before conducting the diagnostic procedure, check for correct installation, proper voltage per unit nameplate, and adequate water supply. Check CB using the steps in "IV.B. Control Board Check." Check the dip switch settings to assure that S4 dip switch 3, 4, 7, 8, 9, & 10 and S5 dip switch 1 through 5 are in the factory default position. S4 dip switch 1, 2, 5, & 6 are cleaning adjustments and the settings are flexible. For factory default settings, see "II.C.2.a) Default Dip Switch Settings." As you go through the procedure, check to assure the components energize and de-energize correctly. If not, those components and controls are suspect.

1)Turn off the power supply, then access the control box. Clear any ice from BC.

2)Turn on the power supply, then move the control switch to the "ICE" position. A 5‑second delay occurs. CB red "POWER OK" LED and green "BC CLOSED" LED come on.

If red "POWER OK" LED is off on thermostatic BC unit (KM-1301SAH-E), clear ice away from the thermostatic bin control bulb in the storage bin area. If no ice is near the thermostatic bin control bulb or the LED does not come on even after clearing away ice, check thermostatic BC. See "IV.C.1. Thermostatic Bin Control Check." If yellow "BC OPEN" LED is on (indicating a full bin), confirm that CB K4 jumper is in place on thermostatic BC unit (KM‑1301SAH-E) or check BC on mechanical BC unit

(KM‑1301SWH-E, KM-1301SRH-E). See "IV.C.2.a) Mechanical Bin Control Check."

3)1-Minute Fill Cycle – LED 4 is on. WV and X2 relay (auxiliary code T-0, U‑0), X11 relay

(auxiliary code U-1 and later) energize and the 1-minute fill cycle begins. After 1 minute,

CB checks for a closed F/S. If F/S is closed, the harvest cycle begins. If closed, continue to step 4. If open, WV remains energized through additional 1‑minute fill cycles until water fills the tank and closes F/S (low water safety). Diagnosis: If WV does not open, check the supply voltage at WV terminals, check continuity on the coil, confirm the screen or external filter isn't plugged (no water flow). If unit fails to start harvest, check for open F/S or bad 1-minute timer in CB. See "IV.D. Float Switch Check and Cleaning" and "IV.B. Control Board Check."

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