4. Control Board Check Procedure

Before replacing a control board that does not show a visible defect and that you suspect is bad, always conduct the following check procedure. This procedure will help you verify your diagnosis.

1)Check the dip switch settings to assure that #3, 4, 7, 8, 9, & 10 are in the factory default position. On units with a slide-type output test switch, the output test switch (S3) should be OFF. Switches 1, 2, 5, & 6 are cleaning adjustments and the settings are flexible.

2)Turn the control switch to ICE and check for proper control voltage. If the red LED is ON, the control voltage is good. If the red LED is OFF, check the control transformer circuit.

3)Check the 115 volt input at the 10-pin connector. Check the brown wire at pin #10 to a white neutral wire for 115 volts. (Always choose a white neutral wire to establish a good neutral connection when checking voltages.) A jumper also feeds 115 volts into pin #7. If no voltage is present, check the 115 volt supply circuit.

4)The output test switch provides a relay sequence test. On units with a slide-type output test switch, move the control switch to the OFF position, move the output test switch to the ON position, then move the control switch to the ICE position. On units with a push- type output test switch, make sure the control switch is in the ICE position, then press the output test switch. The correct lighting sequence should be none, 2, 3, 4, 1, and 4, normal sequence every 5 seconds. Components (e.g., the compressor) will cycle during the test. Note that the order of the relays from the outer edge of the board is 1, 4, 3, 2. Note: If the LEDs light in a different sequence or the 5–second interval does not occur,

the control board is bad and should be replaced.

5)After checking the sequence, place the output test switch back in the OFF position

on units with a slide-type switch. The output test switch must remain in the OFF position during normal operation. On units with a push-type output test switch, the unit automatically resumes normal operation after the test. The unit begins normal operation with the 1 minute fill cycle.

5. Control Board Replacement

The application switch located between relay X3 & X4 must be set to match the original board application. Place this switch in the ALP position if there is no white wire supplied to the K1 connector. If there is a white wire, place the switch in the C position. If this switch is placed in the wrong position either the compressor contactor will remain energized with the control switch OFF or the unit will not start.

The dip switches should be adjusted to the factory default settings as outlined in this manual. Dip switch #8 must remain in the OFF position.

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Hoshizaki KM-501MWH, KM-501MRH, KM-501MAH service manual Control Board Check Procedure, Control Board Replacement
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KM-501MAH, KM-501MWH, KM-501MRH specifications

The Hoshizaki KM-501MWH, KM-501MAH, and KM-501MRH are standout models in the commercial ice machine market, known for their robust performance and innovative technologies. These machines are specially designed to meet the diverse needs of restaurants, bars, and other food service establishments that require a reliable source of high-quality ice.

One of the defining features of the KM-501 series is their high production capacity. Each model can produce up to 500 pounds of ice per day, ensuring that even the busiest establishments can keep up with demand. The ice produced is crystal-clear, with a unique crescent shape that not only looks appealing but also melts slowly, making it ideal for drinks and food presentations.

The KM-501MWH model is equipped with advanced technology that ensures energy efficiency and reduced water usage. It features a powerful compressor and a highly efficient evaporator, which work together to minimize energy consumption while maximizing output. This makes it an environmentally friendly choice, reducing operational costs for businesses.

The KM-501MAH model stands out with its air-cooled condenser system, which allows for optimal performance without the need for extensive cooling water lines. This makes the installation process easier and reduces complexity, enabling businesses to set up their ice machine with minimal hassle. Furthermore, it features a self-cleaning mode that simplifies maintenance, contributing to consistent ice quality over time.

On the other hand, the KM-501MRH is designed for rugged environments. It is constructed with high-quality materials that enhance durability and longevity, making it suitable for outdoor applications or establishments located in warmer climates. The stainless-steel design not only contributes to the machine's robustness but also ensures easy cleaning and resistance to rust and corrosion.

Another key characteristic of the Hoshizaki KM-501 models is their user-friendly control panel. These machines come with intuitive controls that allow operators to easily adjust settings and monitor performance. This feature is particularly useful for staff in busy kitchens, enabling them to focus on service without constant checks on ice production.

Overall, the Hoshizaki KM-501MWH, KM-501MAH, and KM-501MRH offer excellent performance, energy efficiency, and user-friendliness. Their combination of innovative technologies, durable design, and high output capacity make them exceptional choices for any establishment in need of reliable ice production. Whether for a bustling restaurant or a bar serving up cocktails, these machines deliver ice that consistently meets high standards.
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