Panasonic CU-4KS31NBU Case Refrigerant is Leaking, Welding leaking points, Recharging

9-6. In Case Refrigerant is Leaking

CAUTION

(1) Detecting Leaks

Never attempt to charge additional refrigerant when refrigerant has been leaking from the unit. Follow the procedure described below to locate points of leaks and carry out repairs, then recharge the refrigerant.

Use the detector for R410A to locate refrigerant leak points.

(2) Recovering refrigerant

Never release the gas to the atmosphere; recover residual refrigerant using the refrigerant recovery unit for R410A, instead.

(1) Detect leaks

OK

Do not reuse the recovered refrigerant because its composition will have been altered.

(3) Welding leaking points

Confirm again that no residual refrigerant exists in the unit before starting welding.

Weld securely using flux and wax for R410A.

Prevent oxide film from forming inside the tubes utilizing substitution with nitrogen (N2) in the refrigerant circuit of the unit. Leave ends of tubes open during welding.

(2)Recover refrigerant

OK

(3)Weld leaking points

OK

(4) Checking for sealing

Use nitrogen gas for the pressurized gas, and never use a refrigerant other than R410A. Also do not use oxygen or any flammable gas.

(5) Evacuation

Use a solenoid valve-installed vacuum pump so that even if power is cut off in the middle of evacuation of air due to a power interruption, the valve will prevent the pump oil from flowing back.

The equipment may be damaged if moisture remains in the tubing, thus carry out the evacuation thoroughly.

When using a vacuum pump with exhaust air volume more than 0.883 cu.ft./min. and ultimate vacuum pressure rate of 50 micron Hg.

(4)Check for sealing

OK

(5)Evacuation

OK

(6) Recharge

Standard time for evacuation

Length of tubing	Less than 33 ft. (10 m)	More than 33 ft. (10 m)
Evacuation time	More than 10 minutes	More than 15 minutes

(6) Recharging

Recharge unit in the same manner explained on the previous page "(5) Recharging."

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