Panasonic CU-4KS31NBU service manual Adapter manual, and use the adapter correctly

Perform the air purge for tubes A, B, C, and D. Use the same procedures for all tubes.

(1)Check that each tube (both narrow and wide tubes) between the indoor and outdoor units have been proper- ly connected and all wiring for the test run has been completed. Note that both narrow and wide tube service valves on the outdoor unit are kept closed at this stage.

(2)Using an adjustable wrench or box wrench, remove the valve caps from the service valve on both narrow and wide tubes.

(3)Connect a vacuum pump and a manifold valve (with pressure gauges) to the service port on the wide tube service valve. (Fig. 20).

Before using the vacuum pump CAUTION adapter, read the vacuum pump

adapter manual, and use the adapter correctly.

Stopper	Cap tightening torque:
Spindle	170 – 215 lbs·in
Service port	(200 – 250 kgf·cm)
	(Tighten by hand, then
Screw diameter: 1/2
	use a wrench to turn
UNF 20 threads
	approximately
Valve core	45°.)
Cap nut tightening torque:
60 – 95 lbs·in
(70 – 110 kgf·cm)
(Tighten by hand, then use a
wrench to turn approximately 30 .)

<Structure of service valve on wide tube side>

NOTE

External diameter of service port

R410A: 5/16"

Fig. 21

CAUTION

Be sure to use a manifold valve for air purging. If it is not available, use a stop valve for this purpose. The “Hi” knob of the manifold valve must always be kept closed.

When using a hex wrench to open the spindle, an extremely small amount of refrigerant may leak. This does not indicate a problem.

Use a hex wrench of a type to which force can be easily applied.

(4)With the “Lo” knob of the manifold valve open and high-pressure valve (“Hi”) closed completely, run the vacuum pump. Run the pump until the pressure is –101 kPa (–76 cmHg). The operation time for the vacuum pump varies with tubing length and the capacity of the pump. The following table shows the amount of time required for evacuation:

Table 5

Required time for evacuation when capacity

of 100 liter/h vacuum pump is used

20 min. or more

NOTE

The required time in Table 5 is calculated based on the assumption that the ideal (or target) vacuum condition is around 10 mmHg abs.

(5)With the vacuum pump still running, close the “Lo” knob of the manifold valve. Then stop the vacuum pump. Fully close the low-pressure valve and stop the vacuum pump. (Wait 1 – 2 minutes and check that the manifold gauge pointer does not return. If it does return, find and repair the leak, then apply the vacuum again.)

(6)With a hex wrench, turn the valve stem on the narrow tube service valve counter-clockwise by 90 degrees (1/4 turn) for 10 seconds, and then turn the stem clockwise to close it again.

CAUTION

Be sure to completely insert the hex wrench before attempting to turn the valve.

(7)With a standard screwdriver, turn the wide tube service valve stem counterclockwise to fully open the valve.

(8)Turn the narrow tube service valve stem counter-clockwise to fully open the valve.

(9)Loosen the vacuum hose connected to the wide tube service port slightly to release the pressure. Then, remove the hose.

(10)Leak test all joints at the tubing (both indoor and outdoors) with liquid soap. Bubbles indicate a leak. Be sure to wipe off the soap with a clean cloth.

CAUTION

If a CFC gas detector is used, use a special detector for HFC refrigerant (such as R410A and R134a).

20