Service Procedure For Retrofitted A/C Systems (NTB94-091)

PRECAUTIONS FOR WORKING WITH HFC-134A (R-134A)

• CFC-12 (R-12) refrigerant and HFC-134a (R-134a) refrigerant are not compatible. These refrigerants must never be mixed, even in the smallest amounts. If the refrigerants are mixed, compressor failure is likely to occur.
• Use only specified lubricant for the HFC-134a (R-134a) A/C system and HFC-134a (R-134a) components. If lubricant other than that specified is used, compressor failure is likely to occur.
• The specified HFC-134a (R-134a) lubricant rapidly absorbs moisture from the atmosphere. The following handling precautions must be observed:
  1. When removing refrigerant components from a vehicle, immediately cap (seal) the component to minimize the entry of moisture from the atmosphere.
  2. When installing refrigerant components to a vehicle, do not remove the caps (unseal) until just before connecting the components. Connect all refrigerant loop components as quickly as possible to minimize the entry of moisture into system.
  3. Only use the specified lubricant from a sealed container. Immediately reseal containers of lubricant. Without proper sealing, lubricant will become moisture saturated and should not be used.
  4. Avoid breathing A/C refrigerant and lubricant vapor or mist. Exposure may irritate eyes, nose and throat. Remove HFC-134a (R-134a) from A/C system, using certified service equipment meeting requirements of SAE J2210 (R-134a recycling equipment), or J2209 (R-134a recovery equipment). If accidental system discharge occurs, ventilate work area before resuming service. Additional health and safety information may be obtained from refrigerant and lubricant manufacturers.
  5. Do not allow lubricant (Nissan A/C System Oil Type S) to come in contact with styrofoam parts. Damage may result.

GENERAL REFRIGERANT PRECAUTIONS

• Do not release refrigerant into the air. Use approved recovery/ recycling equipment to capture the refrigerant every time an air conditioning system is discharged.
• Always wear eye and hand protection (goggles and gloves) when working with any refrigerant or air conditioning system.
• Do not store or heat refrigerant containers above 52°C (125°F).
• Do not heat a refrigerant container with an open flame; if container warming is required, place the bottom of the container in a warm pail of water.
• Do not intentionally drop, puncture, or incinerate refrigerant containers.
• Keep refrigerant away from open flames; poisonous gas will be produced if refrigerant burns.
• Refrigerant will displace oxygen, therefore be certain to work in well ventilated areas to prevent suffocation.
• Do not introduce compressed air to any refrigerant container or refrigerant component.

PRECAUTIONS FOR REFRIGERANT SERVICE

• When the compressor is removed, store it in the same position as it is when mounted on the car. Failure to do so will cause lubricant to enter the low pressure chamber.
• When connecting tubes, always use a torque wrench and a back-up wrench. See Fig 3 .
• After disconnecting tubes, immediately plug all openings to prevent entry of dirt and moisture. See Fig 4 .
• When installing an air conditioner in the vehicle, connect the pipes as the final stage of the operation. Do not remove the seal caps of pipes and other components until just before required for connection.
• Allow components stored in cool areas to warm to working area temperature before removing seal caps. This prevents condensation from forming inside A/C components.
• Thoroughly remove moisture from the refrigeration system before charging the refrigerant.
• Always replace used O-rings.
• When connecting tube, apply lubricant to portions shown in Fig 5 . Be careful not to apply lubricant to threaded portion.
• Lubricant Name: Nissan A/C System Oil Type S (For swash plate type compressor and V-6 compressor); Nissan A/C System Oil Type R (For vane rotary type compressor)

Part Number: KLH00-PAGS1 (For swash plate type compressor and V-6 compressor);

KLH00-PAGR1 (For vane rotary type compressor)

• O-ring must be closely attached to inflated portion of tube. See Fig 5 .
• After inserting tube into union until O-ring is no longer visible, tighten nut to specified torque. See Fig 6 .
• After connecting line, conduct leak test and make sure that there is no leakage from connections. See Fig 7 . When gas leaking point is found, disconnect that line and replace the O-ring. Then tighten connections of seal seat to the specified torque.

PRECAUTIONS FOR SERVICING COMPRESSOR

• Plug all openings to prevent moisture and foreign matter from entering. When the compressor is removed, store it in the same position as it is when mounted on the car.
• When replacing or repairing compressor, follow "Maintenance of Lubricant Quantity in Compressor" exactly.
• Keep friction surfaces between clutch and pulley clean. If the surface is contaminated with lubricant, wipe it off by using a clean waste cloth moistened with thinner.
• After compressor service operation, turn the compressor shaft by hand more than five turns in both directions. This will equally distribute lubricant inside the compressor. After the compressor is installed, let the engine idle and operate the compressor for one hour.
• After replacing the compressor magnet clutch, apply voltage to the new one and check for normal operation.

HFC-134A (R-134A) SERVICE TOOLS AND EQUIPMENT

Refrigerant container fittings, service hose fittings, and service equipment fittings (equipment which handles refrigerant and/or lubricant) are different between CFC-12 (R-12) and HFC-134a (R-134a). This is to avoid mixed use of the refrigerants/lubricant.

RECOVERY/RECYCLING/RECHARGING EQUIPMENT

Be certain to follow the manufacturers instructions for machine operation and machine maintenance. Never introduce any refrigerant other than that specified into the machine.

ELECTRONIC LEAK DETECTOR

Be certain to follow the manufacturers instructions for tester operation and tester maintenance.

VACUUM PUMP

The lubricant contained inside the vacuum pump is not compatible with the specified lubricant for HFC-134a (R-134a) A/C systems. The vent side of the vacuum pump is exposed to atmospheric pressure, so the vacuum pump lubricant may migrate out of the pump into the service hose. This is possible when the pump is switched off after evacuation (vacuuming) and hose is connected to it.

To prevent this migration, use a manual valve placed near the hose-to-pump connection, as described below:

• Usually vacuum pumps have a manual isolator valve as part of the pump. See Fig 17 . Close this valve to isolate the service hose from the pump.
• For pumps without an isolator, use a hose equipped with a manual shut-off valve near the pump end. See Fig 17 . Close the valve to isolate the hose from the pump.
• If the hose has an automatic shut off valve, disconnect the hose from the pump. As long as the hose is connected, the valve is open and lubricating oil may migrate.

Some one-way valves open when vacuum is applied and close under a no vacuum condition. Such valves may restrict the pump's ability to pull a deep vacuum and are not recommended.

MANIFOLD GAUGE SET

Be certain that the gauge face indicates R-134a or 134a. Be sure the gauge set has 1/2"-16 ACME threaded connections for service hoses. Confirm the set has been used only with refrigerant HFC-134a (R-134a) and specified lubricants. See Fig 18 .

SERVICE HOSES

Be certain that the service hoses display the markings described (colored hose with black stripe). See Fig 19 . All hoses must include positive shut off devices (either manual or automatic) near the end of the hoses opposite the manifold gauge. See Fig 20 .

SERVICE COUPLERS

Never attempt to connect HFC1-34a (R-134a) service couplers to a CFC-12 (R-12) A/C system. The HFC-134a (R-134a) couplers will not properly connect to the CFC-12 (R-12) system. However, if an improper connection is attempted, discharging and contamination may occur.

REFRIGERANT WEIGHT SCALE

Verify that no refrigerant other than HFC-134a (R-134a) and specified lubricants have been used with the scale. If the scale controls refrigerant flow electronically, the hose fitting must be 1/2"-16 ACME. See Fig 21 .

PERFORMANCE DATA

General performance characteristics for the CFC-12 (R-12) A/C system and the retrofit A/C system differ. These differences are outlined below.

Recirculating-to-Discharge Air Temperature

• The retrofitted A/C system retains the original CFC-12 (R-12) heat exchanger (evaporator and condenser).
• Some CFC-12 (R-12) lubrication oil remains in the A/C system.
• Because of these two stated reasons the retrofit A/C system has a slightly lower cooling capacity than the CFC-12 (R-12) A/C system. [Maximum discharge air temperature is increased by approximately 2°C (3.6°F).]

Ambient Air Temperature-to-Operating Pressure

The retrofit A/C system has a higher operating pressure than the CFC-12 (R-12) A/C system when the outside air temperature exceeds 15°C (59°F).

• High-pressure side (Discharge side): Maximum pressure increase of approximately 294 kPa (3 kg/cm² , 43 psi)
• Low-pressure side (Suction side): Same as CFC-12 (R-12) A/C system

Refer to Service Manuals for discharge air temperature and operating pressure values for individual vehicle models. Refer to these Manuals for CFC-12 (R-12) A/C system values.

SETTING OF SERVICE TOOLS AND EQUIPMENT

Discharging Refrigerant

Remove HFC-134a (R-134a) from A/C system using certified service equipment meeting requirements of SAE J2210 [HFC-134a (R-134a) recycling equipment] or J2209 [HFC-134a (R -134a) recovery equipment]. If accidental system discharge occurs, ventilate work area before resuming service. Additional health and safety information may be obtained from refrigerant and lubricant manufacturers. See Fig 28 .

Evacuating System and Charging Refrigerant

See Fig 29 .

MAINTENANCE OF LUBRICANT QUANTITY IN COMPRESSOR

The lubricant used to lubricate the compressor circulates through the system with the refrigerant. Add lubricant to compressor when replacing any component or after repairing a large gas leak. It is important to maintain the specified amount. If lubricant quantity is not maintained properly, the following malfunctions may result:

• Lack of lubricant: May lead to a seized compressor
• Excessive lubricant: Inadequate cooling (thermal exchange interference)

Lubricant

1. Swash Plate Compressor And V-6 Compressor

Name: Nissan A/C System Oil Type S

Part number: KLH00-PAGS1

1. Vane Rotary Compressor

Name: Nissan A/C System Oil Type R

Part number: KLH00-PAGR1

CHECKING AND ADJUSTING

Adjust the lubricant quantity according to the following flowchart.

Fig 43: LUBRICANT QUANTITY FLOWCHART (1 OF 2)

Fig 44: LUBRICANT QUANTITY FLOWCHART (2 OF 2)

Fig 45: FLOW CHART C (MAINTENANCE OF LUBRICANT QTY.)