Hoshizaki KM-320MWH, KM-320MAH service manual Defrost Control

Page 17

a) Defrost Control

A thermistor (semiconductor) is used for a defrost control sensor. The resistance varies depending on the suction line temperatures. The thermistor detects the temperature of the evaporator outlet to start the defrost timer. No adjustment is required. If necessary, check for resistance between thermistor leads, and visually check the thermistor mounting, located on the suction line next to the evaporator outlet.

Temperature (°F)

Temperature (°C)

Resistance (k)

 

 

 

0

-18

14.401

10

-12

10.613

32

0

6.000

50

10

3.871

70

21

2.474

90

32

1.633

Check a thermistor for resistance by using the following procedure:

1)Disconnect the connector K3 on the board.

2)Remove the thermistor. See "V.H. Removal and Replacement of Thermistor."

3)Immerse the thermistor sensor portion in a glass containing ice and water for 2 or 3 minutes.

4)Check for a resistance between thermistor leads. Normal reading is within 3.5 to 7 k. Replace the thermistor if it exceeds the normal reading.

b)Defrost Timer

No adjustment is required under normal use, as the defrost timer is adjusted to the suitable position. However, if necessary when all the ice formed on the evaporator does not fall into the bin in the harvest cycle, adjust the defrost timer to longer setting by adjusting the dip switch (No. 1 & 2) on the controller board.

Dip Switch Setting

Time

No. 1

No. 2

(seconds)

 

OFF

OFF

60

ON

OFF

90

OFF

ON

120

ON

ON

180

17

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Contents KM-320MAH KM-320MWH Hoshizaki AMERICA, INC Contents Page Approximate Storage Capacity Electric & Water Consumption Specifications KM-320MAH air-cooledWater Cooled Condenser KM-320MWH water-cooledKM-320MAH air-cooled II. General Information ConstructionKM-320MWH water-cooled Controller Board Features of Control Products E Controller BoardSolid-State Control Controller BoardHigh Temperature Safety 127 ± 7F 53 ± 4C LED Control Products HOS-001A Board Sequence 1st Cycle 2nd Cycle and after with pump drain 2nd Cycle and after with no pump drain Controls and Adjustments Defrost Control Drain Timer Checking the Controller Board Freeze TimerPage KM-320MAH KM-320MWH KM-320MAH, KM-320MWH Wiring DiagramTiming Chart Page 117 Performance Data352 Problem Possible Cause Remedy IV. Service Diagnosis No Ice ProductionProblem Possible Cause Remedy Problem Possible Cause Remedy Evaporator is Frozen Up Problem Possible Cause Remedy Other Low Ice ProductionAbnormal Ice Service for Refrigerant Lines Removal and Replacement of ComponentsRefrigerant Recovery Evacuation and Recharge R-404ABrazing Removal and Replacement of Compressor Removal and Replacement of Expansion Valve Removal and Replacement of DrierRemoval and Replacement of Hot Gas Valve and Line Valve Removal and Replacement of Evaporator Removal and Replacement of Thermistor Removal and Replacement of Water Valve Removal and Replacement of Fan MotorRemoval and Replacement of Spray Tubes Removal and Replacement of Pump MotorPage Adjustment Of Water Regulating Valve Water-Cooled Model Only Preparing the Icemaker for Long Storage VI. Cleaning and Maintenance InstructionsPage Cleaning and Sanitizing Instructions Cleaning Procedure Sanitizing Procedure Following Cleaning Procedure Stainless Steel Exterior MaintenanceStorage Bin and Scoop Condenser except water-cooled model
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KM-320MWH, KM-320MAH specifications

Hoshizaki, a leading manufacturer in the food service equipment sector, offers a diverse range of ice-making machines that excel in efficiency, durability, and innovative technology. Among the notable models are the Hoshizaki MWH KM-515MAH, MWH(-M), MRH KM-901MAH, MRH KM-600MAH, KM-650MAH, and KM-320MAH. Each model brings unique features designed to meet varying commercial ice production needs.

The Hoshizaki MWH KM-515MAH is particularly recognized for its high ice production capacity, generating up to 515 pounds of ice per day. This model incorporates advanced technology that ensures consistent ice quality and purity. The MWH(-M) variant often includes modifications to suit specific operational environments, ensuring reliability in diverse settings.

Similarly, the MRH KM-901MAH stands out with its ability to produce a staggering 901 pounds of ice per day, making it ideal for high-volume establishments. This model is equipped with Hoshizaki's unique "cubelet" technology, producing a soft, chewable ice perfect for beverages. It also features a robust stainless steel construction, enhancing its durability and resistance to corrosion.

The MRH KM-600MAH offers 600 pounds of daily ice output, while the KM-650MAH enhances that capacity to 650 pounds. Both machines prioritize energy efficiency and come with built-in energy-saving modes. These models feature advanced ice sensing technology that monitors production levels to optimize energy consumption and reduce waste.

On the other hand, the KM-320MAH is designed for smaller establishments, with a daily ice production rate of 320 pounds. Despite its smaller footprint, it maintains high production efficiency and is equipped with features like a built-in storage bin, saving space while ensuring a reliable ice supply.

Across these models, Hoshizaki employs various technologies, including air-cooled and water-cooled systems, offering flexibility depending on installation requirements. The ice machines are designed with user-friendly controls and features like self-cleaning capabilities, making maintenance straightforward and less time-consuming.

In summary, Hoshizaki's ice machines, including the MWH KM-515MAH, MRH KM-901MAH, and others, deliver exceptional ice production, durability, and efficiency tailored to meet the demands of any commercial kitchen or service establishment. With a commitment to quality, Hoshizaki continues to be a trusted choice for businesses needing reliable ice-making solutions.