Hoshizaki KM-2500SWH3 - Manual (Page 28)

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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. The maximum allowable voltage variation is ±10 percent of the nameplate
rating. Check the dip switch settings to assure that S4 dip switch 3, 4, 7, 8, 9, & 10 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.4.a) Default Dip Switch
Settings." Check CB using the steps in "IV.B. Control Board Check." As you go through
the diagnostic procedure, check to assure the components energize and de-energize
correctly. If not, those components or controls are suspect. Always choose a white (W)
neutral wire to establish a good neutral connection when checking high voltages.
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. The red "POWER OK" LED on CB comes on.
3) 1-Minute Fill Cycle – LED 4 is on. WV energizes. After 1 minute, CB checks for a
closed F/S. If F/S is closed, 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 for 115VAC
at WV terminals. If 115VAC is not present, CB is defective and must be replaced. If
115VAC is present, check continuity of WV coil, confirm the screen or external filter
is not 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."