(7) Electric expansion valve

When replacing the electric expansion valve and coil, be sure to attach the connectors in the correct positions. Labels are applied to the valve body and coil, corresponding to the connector colors, to identify them.

Controller check

 

 

 

 

No voltage on circuit board

Voltage varies

 

 

 

 

Use a multi-meter to measure the voltage (12 V).

When the power is turned ON, the needle will move in the following seguence in approximately 10 to 20 seconds for each point.

Model No.

 

 

Sequence

CU-3KE19NBU

MV0

 

MV1

 

MV2

 

 

CU-4KE24NBU CU-4KE31NBU

MV0 MV1 MV2 MV3

Check the illumination of the red Power Lamp.

Replace the controller.

NOTE

Cool the main unit with a damp cloth or other means while welding. When applying vacuum, use the special service magnet and rotate at least 5 revolutions counterclockwise to fully open the electric expansion valve.

Check the coil resistance.

 

 

Check the resistance between the gray lead

 

 

 

 

 

 

 

 

wire and the other wires.

 

 

 

 

 

 

 

 

 

 

 

 

Resistance is OK if it is 46 + / – 4ohm at 68 °F

0 ohm

Approx. 46 +/– 4 ohm

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

*1

 

 

 

Use the special service magnet and

 

Replace the coil.

 

 

 

 

 

 

 

Open and close the

 

 

 

 

 

 

 

 

 

 

 

 

 

rotate 5 revolutions clockwise to fully

 

 

 

 

 

 

 

 

 

 

 

electric expansion valve

 

 

 

 

close the valve.

 

 

 

 

 

 

 

 

 

by hand to check it.

 

 

 

Then start the unit and measure the

 

 

 

 

 

 

 

 

 

 

 

 

 

 

temperature at the inlet and outlet

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

No temperature change

 

 

Temperature changes

tubes of the electric expansion valve.

 

 

 

 

 

If the temperature difference is large,

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

the valve is closed.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Then rotate 5 revolutions

 

 

 

Replace the electric

 

 

This part is normal.

 

counterclockwise to open the valve.

 

 

 

expansion valve.

 

 

Check elsewhere.

 

Operation is normal if the temperature

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

difference between the 2 tubes drops.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

*1 If you have manually checked the electric expansion valve, be sure to reapply the outdoor power after you have replaced the wiring. (The position of the elecric expansion valve will changed.)

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Panasonic service manual Electric expansion valve, CU-3KE19NBU MV0 MV1 MV2 CU-4KE24NBU CU-4KE31NBU
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CU-3KE19NBU, CU-4KE24NBU, CU-4KE31NBU specifications

The Panasonic CU-4KE24NBU, CU-4KE31NBU, and CU-3KE19NBU are high-efficiency air conditioning units that represent Panasonic's commitment to innovative climate control solutions. These models integrate advanced technologies to deliver superior performance, energy savings, and user comfort, making them ideal for both residential and commercial applications.

The CU-4KE24NBU, a part of the ECOi series, is designed for medium-sized spaces. It boasts an impressive cooling capacity, ensuring optimal temperature regulation. Its inverter technology adjusts the compressor speed according to the needs of the environment, resulting in reduced energy consumption and consistent comfort levels. The unit operates quietly, making it suitable for bedrooms, offices, or other noise-sensitive environments. Additionally, it features a robust air filtration system that improves indoor air quality by removing dust and allergens.

The CU-4KE31NBU offers a slightly higher capacity, making it perfect for larger areas. Like its counterpart, it utilizes inverter technology, which not only enhances energy efficiency but also minimizes wear and tear on the components, leading to a longer lifespan. Its multi-split capability allows for the connection of multiple indoor units to a single outdoor unit, providing flexibility in installation. The CU-4KE31NBU also integrates smart technology that allows users to control the system remotely via smartphones, giving them greater convenience and control over their environment.

For applications requiring a more compact option, the CU-3KE19NBU is an excellent choice. This model balances size and power, offering a competitive cooling capacity that can easily service small to medium-sized rooms. The unit is designed for easy installation and maintenance, featuring a lightweight construction that simplifies handling by technicians. The efficient inverter technology ensures that users benefit from lower energy bills while maintaining a consistent indoor climate.

All three models are equipped with Panasonic’s advanced refrigerants, which contribute to their eco-friendly performance. These refrigerants help reduce greenhouse gas emissions while maintaining high efficiency. Moreover, the units come with built-in diagnostic capabilities, allowing for quick detection of any issues, thus ensuring that the systems operate at peak efficiency throughout their lifespan.

In summary, the Panasonic CU-4KE24NBU, CU-4KE31NBU, and CU-3KE19NBU are exemplary air conditioning solutions that combine cutting-edge technology with user-friendly features, ensuring that they meet the varying needs of today's consumers while promoting energy efficiency and sustainability.
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