Panasonic CU-4KS31NBU service manual Pump Down, gas without releasing it into the atmosphere

(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

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