Problem Possible Cause Remedy | Hoshizaki KM-901MAH, KM-901MWH

Problem	Possible Cause			Remedy

[1]Freeze cycle time is	f)	Thermistor	1. Disconnected, loose,	1. Connect, secure, check.
too long. (continued)			or defective.	See "V.L. Removal
				and Replacement of
				Thermistor."
	g) Refrigerant		1. Low charge.	1. Check for leaks. Recover,
				repair, evacuate, and
				recharge.

	h) Expansion Valve		1. Bulb loose.	1. Secure bulb.

			2. Operating erratically.	2. Check and replace.

	i)	Control Board	1. Defective.	1. See "IV.B. Control Board
				Check."
[2]All ice formed on	a) Evaporator		1. Scaled up.	1. Clean.
evaporator does not			2. Damaged.	2. Replace.
fall into bin in harvest			2. Damaged.	2. Replace.

	b) Ambient and/or Water		1. Too cool.	1. Increase temperature.
cycle.		Temperature
		Temperature

	c) Water Supply Line		1. Water pressure too	1. Check and get
			low.	recommended pressure.

	d) Water System		1. Water supply line	1. Increase water line size.
			too small; requires
			3/8" OD line dedicated
			per machine.
			2. Water filter clogged or	2. Replace filter or install a
			flow rate too small.	higher flow rate filter.

	e) Inlet Water Valve		1. Dirty mesh filter or	1. Clean.
			orifice.

			2. Diaphragm does not	2. Check for water leaks with
			close.	icemaker off.

	f)	Spray Tubes	1. Dirty.	1. Clean.
			2. Out of position.	2. Place in position.

	g) Thermistor		1. Disconnected, loose,	1. Connect, secure, check.
			or defective.	See "V.L. Removal
				and Replacement of
				Thermistor."

	h) Hot Gas Valve		1. Coil winding open.	1. Replace.

			2. Plunger does not	2. Replace.
			move.
			3. Wiring to hot gas	3. Check for loose
			valve.	connection or open, and
				replace.

	i)	Expansion Valve	1. Bulb loose.	1. Secure bulb.

			2. Operating erratically.	2. Check and replace.

	j)	Liquid Line Valve	1. Continues to open in	1. Check operation in harvest
		(if applicable)	harvest cycle.	cycle and replace.
	k) Control Board		1. Harvest timer is set	1. Adjust longer, referring to
			too short.	"II.C.3.b) Harvest Timer
				(S4 dip switch 1 & 2)."

			2. Defective.	2. See "IV.B. Control Board
				Check."

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Hoshizaki KM-901MAH, KM-901MWH, KM-901MRH/3 service manual Problem Possible Cause Remedy

Contents

KM-901MAH KM-901MWH Hoshizaki AMERICA, INC Contents Page Page Important Safety Information Serious injuryIndicates important information about the use and care Unit Specifications Icemaker 1a. KM-901MAH air-cooled Auxiliary Code T-0, U-0 1b. KM-901MAH air-cooled Auxiliary Code U-1 and Later 2a. KM-901MWH water-cooled Auxiliary Code T-0, U-0 Water Cooled Condenser 2b. KM-901MWH water-cooled Auxiliary Code U-1 and Later 3a. KM-901MRH remote air-cooled Auxiliary Code T-0, U-0 3b. KM-901MRH remote air-cooled Auxiliary Code U-1 and Later 4a. KM-901MRH3 remote air-cooled Auxiliary Code T-0, U-0 4b. KM-901MRH remote air-cooled Auxiliary Code U-1 and Later Condenser Unit Specifications Model URC-9F II. General Information Construction KM-901MAH air-cooled KM-901MWH water-cooled KM-901MRH/3 remote air-cooled Sequence Cycles and Shutdown Sequence of OperationControl Board Auxiliary Code T-0, U-0 Shutdown Control Board Auxiliary Code U-1 and Later OFF Cycle at Shutdown Mechanical Bin Control Activation Control Board Sequence Flow Chart Sequence Flow ChartCycle Bin Full Control Board Auxiliary Code U-1 LaterMinute Harvest Cycle Freeze Cycle Pump-Out Cycle Fill Cycle Control Board Control Board Layout Control Board Part Number 2A3792-01 Harvest Backup Timer and Freeze Timer High Temperature SafetyLow Water Safety Maximum Water Supply Period 6 minutes LED Lights and Audible Alarm Safeties No. of Beeps Type of Alarm Every 3 secSequence Step Energized Time LEDs are On Components Min Max Avg Control Board Auxiliary Code U-1 and Later Controls and Adjustments Default Dip Switch SettingsHarvest Timer S4 dip switch 1 S4 Dip Switch S4 Dip Switch No Pump-Out Frequency Control S4 dip switch 5 Pump-Out Timer S4 dip switch 3S4 Dip Switch Setting Time seconds Inlet Bin Control Selector/Harvest Pump Timer S4 dip switch Factory Use S4 dip switchControl Board S4 Dip Switch Setting Bin Control Control Board S4 Dip Switch Setting Pump Motor Time seconds Freeze Timer S4 dip switch 9 Float Switch Control S5 dip switch 1 G Control BoardRefill Counter S5 dip switch 2 through 5 G Control Board S4 Dip Switch Setting Time Minutes Float Switch Control SwitchBin Control Thermistor Water Pump Switch Discharge Line ModelCooled-AirWater-Cooled Model PressureHigh* Switch Wiring DiagramsKM-901MAH air-cooled and KM-901MWH water-cooled KM-901MRH remote air-cooled PressureSwitchHigh KM-901MRH3 remote air-cooled Switch Cooled-WaterModel Cooled-AirModel High* Pressure High Pressure Switch SwitchPressure Performance Data 912 8351480 1570 KM-901MRH remote air-cooled KM-901MRH3 remote air-cooled IV. Service Diagnosis Diagnostic ProcedurePage OFF Control Board Check Shutdown Thermostatic Bin Control Auxiliary Code T-0, U-0 Bin Control Check Control Correct LED Board Lighting Sequence Mechanical Bin Control Check Mechanical Bin Control Cleaning Float Switch Check and Cleaning Float Switch Check Float Switch Cleaning Thermistor Check Problem Possible Cause Remedy Diagnostic ChartsNo Ice Production Problem Possible Cause Remedy Problem Possible Cause Remedy Evaporator is Frozen Up Problem Possible Cause Remedy Low Ice Production Abnormal Ice Other Service for Refrigerant Lines Removal and Replacement of ComponentsRefrigerant Recovery Brazing Evacuation and Recharge R-404A Removal and Replacement of Compressor Removal and Replacement of Expansion Valve Page Removal and Replacement of Evaporator Removal and Replacement of Air-Cooled Condenser Removal and Replacement of Water-Cooled Condenser Removal and Replacement of Remote Air-Cooled Condenser Page Adjustment of Water Regulating Valve water-cooled model Removal and Replacement of Thermistor Removal and Replacement of Inlet Water Valve Removal and Replacement of Pump Motor Removal and Replacement of Control Board VI. Cleaning and Maintenance Cleaning and Sanitizing Instructions Cleaning Procedure Sanitizing Procedure Following Cleaning Procedure Maintenance Preparing the Icemaker for Long Storage Drain the water tank