1998 NISSAN PATROL Heather And Air Conditioner Workshop Manual

HFC-134a (R-134a) Service Tools and
Equipment
Never mix HFC-134a refrigerant and/or its speci®ed lubricant with CFC-12 (R-12) refrigerant and/or its lubri-
cant.
Separate and non-interchangeable service equipment must be used for each type of refrigerant/lubricant.
Refrigerant container ®ttings, service hose ®ttings and service equipment ®ttings (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.
Adapters that convert one size ®tting to another must never be used: refrigerant/lubricant contamination will
occur and compressor failure will result.
Tool name Description Note
HFC-134a (R-134a) refrig-
erant
NT196
Container color: Light blue
Container marking: HFC-134a (R-134a)
Fitting size: Thread size
+large container 1/2²-16 ACME
Nissan A/C System Oil
Type S
NT197
Type: Poly alkylene glycol oil (PAG), type S
Application: HFC-134a (R-134a) swash plate
(piston) compressors (Nissan only)
Lubricity: 40 m!(1.4 Imp ¯ oz)
Recovery/Recycling/
Recharging equipment
NT195
Function: Refrigerant Recovery and Recycling
and Recharging
Electrical leak detector
NT198
Power supply:
+DC 12V (Cigarette lighter)
Manifold gauge set (with
hoses and couplers)
NT199
Identi®cation:
+The gauge face indicates R-134a.
Fitting size: Thread size
+1/2²-16 ACME
PRECAUTIONS AND PREPARATIONMANUAL AND AUTO
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Tool name Description Note
Service hoses
+High side hose
+Low side hose
+Utility hose
NT201
Hose color:
+Low hose: Blue with black stripe
+High hose: Red with black stripe
+Utility hose: Yellow with black stripe or
green with black stripe
Hose ®tting to gauge:
+1/2²-16 ACME
Service couplers
+High side coupler
+Low side coupler
NT202
Hose ®tting to service hose:
+M14 x 1.5 ®tting is optional or
permanently attached.
Refrigerant weight scale
NT200
For measuring of refrigerant
Fitting size: Thread size
+1/2²-16 ACME
Vacuum pump
(Including the isolator
valve)
NT203
Capacity:
+Air displacement: 4 CFM
+Micron rating: 20 microns
+Oil capacity: 482 g (17 oz)
Fitting size: Thread size
+1/2²-16 ACME
PRECAUTIONS AND PREPARATIONMANUAL AND AUTO
HFC-134a (R-134a) Service Tools and
Equipment (Cont'd)
HA-8

Precautions for Service Equipment
RECOVERY/RECYCLING EQUIPMENT
Follow the manufacturer's instructions for machine operation and
machine maintenance. Never introduce any refrigerant other than
that speci®ed into the machine.
ELECTRONIC LEAK DETECTOR
Follow the manufacture's instructions for tester operation and tester
maintenance.
VACUUM PUMP
The lubricant contained inside the vacuum pump is not compatible
with the speci®ed 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 situated near the
hose-to-pump connection, as follows.
+Usually vacuum pumps have a manual isolator valve as part of
the pump. 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. 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. Make
sure the gauge set has 1/2²-16 ACME threaded connections for
service hoses. Con®rm the set has been used only with refrigerant
HFC-134a (R-134a) along with speci®ed lubricant.
SERVICE HOSES
Be certain that the service hoses display the markings described
(colored hose with black stripe). All hoses must include positive
shut off devices (either manual or automatic) near the end of the
hoses opposite the manifold gauge.
RHA270D
SHA533D
RHA272D
PRECAUTIONS AND PREPARATIONMANUAL AND AUTO
HA-9

SERVICE COUPLERS
Never attempt to connect HFC-134a (R-134a) service couplers to
an 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 contamina-
tion may occur.
Shut-off valve rotation A/C service valve
Clockwise Open
Counterclockwise Close
REFRIGERANT WEIGHT SCALE
Verify that no refrigerant other than HFC-134a (R-134a) and speci-
®ed lubricants have been used with the scale. If the scale controls
refrigerant ¯ow electronically, the hose ®tting must be 1/2²-16
ACME.
CHARGING CYLINDER
Using a charging cylinder is not recommended. Refrigerant may be
vented into air from cylinder's top valve when ®lling the cylinder with
refrigerant. Also, the accuracy of the cylinder is generally less than
that of an electronic scale or of quality recycle/recharge equipment.
RHA273D
RHA274D
PRECAUTIONS AND PREPARATIONMANUAL AND AUTO
Precautions for Service Equipment (Cont'd)
HA-10

Refrigeration Cycle
REFRIGERANT FLOW
The refrigerant ¯ow is in the standard pattern. Refrigerant ¯ows through the compressor, condenser, liquid
tank, evaporator and back to the compressor.
The refrigerant evaporation through the evaporator coil is controlled by an externally equalized expansion
valve, located inside the evaporator case.
FREEZE PROTECTION
The compressor cycles on and off to maintain the evaporator temperature within a speci®ed range. When the
evaporator coil temperature falls below a speci®ed point, the thermo control ampli®er interrupts the compres-
sor operation. When the evaporator coil temperature rises above the speci®cation, the thermo control ampli-
®er allows compressor operation.
REFRIGERANT SYSTEM PROTECTION
Dual-pressure switch
The dual-pressure switch is located on the liquid tank. If the system pressure rises or falls out of specifications,
the switch opens to interrupt compressor clutch operation.
RHA735G
DESCRIPTIONMANUAL AND AUTO
HA-11

Component Layout
RHA699G
DESCRIPTIONMANUAL AND AUTO
HA-12

Discharge Air Flow
RHA700G
DESCRIPTIONMANUAL AND AUTO
HA-13

Wiring Diagram Ð R/HEAT Ð/LHD Models
THA165
TROUBLE DIAGNOSESREAR HEATER
HA-14