(11)Replace the flare nut on the wide tube service port and fasten the flare nut securely with an adjustable wrench or box wrench. Next, mount the valve cap and tighten it with a torque wrench (the cap needs to be tightened with the torque of 180 lbs·in (200 kgf·cm)). This process is very important to prevent gas from leaking from the system.

(12)Test run the air conditioner. (See page 26.)

(13)While the air conditioner is running, apply liquid soap to check for any gas leaks around the service valves or caps.

(14)If there is no leakage, stop the air conditioner.

(15)Wipe off the soap on the tubing.

This completes air purging with a vacuum pump and the air conditioner is ready for actual operation.

Pump Down

In order to protect the earth’s environment, be sure to perform pump-down to recover refrigerant

gas without releasing it into the atmosphere.

When relocating or disposing of the air conditioner, request this service from the dealer where the unit was purchased, or from an appropriate agent. Perform pump-down as described below.

What is pump-down?

Pump-down refers to recovering the refrigerant gas from the refrig- erant cycle at the outdoor unit. This work must be performed dur- ing cooling operation. The refrigerant gas cannot be recovered during heating operation.

During winter, or if the temperature sensor prevents cooling opera- tion, perform “forced cooling operation.”

Pump-down procedure

(1)Fully close the spindles at the valves on the narrow tube side of tubes A, B, C and D. (Refer to Fig. 22.)

(2)Connect the manifold gauge to the charging port at the valve on the wide tube side of tube D. Purge the air from the charging hose. (Refer to Fig. 23.)

(3)Perform cooling operation or forced cooling operation.

When the pressure at the low-pressure side is 0.05 – 0.1 MPaG (0.5 – 1 kg/cm2G), fully close the spindles at the valves on the wide tube side of tubes A, B, C, and D, and immediately stop operation. (Refer to Fig. 23.)

In the winter, the outdoor unit may stop after 5 - 10 minutes of operation. This is in order to protect the indoor unit heat exchanger from freezing and does not indicate a problem.

(4)Disconnect the manifold gauge and the inter-unit tubes, and attach the caps and flare nuts. At this point, pump-down is com- pleted. (If the caps and flare nuts are not reattached, there is the danger of gas leakage.) (Refer to Fig. 24.)

If pump-down is not possible

If the air conditioner cannot be operated because of a malfunction or other cause, use a refrigerant recovery device to recover the refrigerant.

 

Close

 

D

Narrow tube side

Close

 

C

 

Close

 

B

Charging port

Close

 

 

A

 

Fig. 22

 

D

Wide tube side

C

 

 

B

 

A

Charging hose

Manifold gauge

 

 

Fig. 23

Cap

 

Cap

After disconnecting

 

 

the inter-unit tubes,

Cap

attach the flare nuts

with flare bonnets.

Cap

 

Fig. 24

21

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Panasonic CU-4KE31NBU, CU-4KE24NBU Pump Down, What is pump-down?, Pump-down procedure, If pump-down is not possible
Page 116 Page 118

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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