refrigerant type ISUZU AXIOM 2002 Service Repair Manual

HEATING, VENTILATION AND AIR CONDITIONING (HVAC)
1A±19
Evaporation
The refrigerant is changed from a liquid to a gas inside the
evaporator. The refrigerant mist that enters the
evaporator vaporizes readily. The liquid refrigerant
removes the required quantity of heat (latent heat of
vaporization) from the air around the evaporator core
cooling fins and rapidly vaporizes. Removing the heat
cools the air, which is then radiated from the fins and
lowers the temperature of the air inside the vehicle.
The refrigerant liquid sent from the expansion valve and
the vaporized refrigerant gas are both present inside the
evaporator as the liquid is converted to gas.
With this change from liquid to gas, the pressure inside
the evaporator must be kept low enough for vaporization
to occur at a lower temperature. Because of that, the
vaporized refrigerant is sucked into the compressor.
Compression
The refrigerant is compressed by the compressor until it is
easily liquefied at normal temperature.
The vaporized refrigerant in the evaporator is sucked into
the compressor. This action maintains the refrigerant
inside the evaporator at a low pressure so that it can
easily vaporize, even at low temperatures close to 0
C
(32
F).
Also, the refrigerant sucked into the compressor is
compressed inside the cylinder to increase the pressure
and temperature to values such that the refrigerant can
easily liquefy at normal ambient temperatures.
Condensation
The refrigerant inside the condenser is cooled by the
outside air and changes from gas to liquid.
The high temperature, high pressure gas coming from the
compressor is cooled and liquefied by the condenser with
outside air and accumulated in the receiver/drier. The
heat radiated to the outside air by the high temperature,
high pressure gas in the compressor is called heat of
condensation. This is the total quantity of heat (heat of
vaporization) the refrigerant removes from the vehicle
interior via the evaporator and the work (calculated as the
quantity of heat) performed for compression.
Expansion
The expansion valve lowers the pressure of the
refrigerant liquid so that it can easily vaporize.
The process of lowering the pressure to encourage
vaporization before the liquefied refrigerant is sent to the
evaporator is called expansion. In addition, the expansion
valve controls the flow rate of the refrigerant liquid while
decreasing the pressure.
That is, the quantity of refrigerant liquid vaporized inside
the evaporator is determined by the quantity of heat which
must be removed at a prescribed vaporization
temperature. It is important that the quantity of refrigerant
be controlled to exactly the right value.
Compressor
The compressor performs two main functions:It compresses low-pressure and low-temperature
refrigerant vapor from the evaporator into high-pressure
and high-temperature refrigerant vapor to the condenser.
It pumps refrigerant and refrigerant oil through the air
conditioning system.
This vehicle is equipped with a five-vane rotary
compressor.
The specified amount of the compressor oil is 150cc
(5.0 fl. oz.).
The oil used in the HFC-134a system compressor differs
from that used in R-12 systems.
Also, compressor oil to be used varies according to the
compressor model. Be sure to avoid mixing two or more
different types of oil.
If the wrong oil is used, lubrication will be poor and the
compressor will seize or malfunction.
The magnetic clutch connector is a waterproof type.
Magnetic Clutch
The compressor is driven by the drive belt from the crank
pulley of the engine. If the compressor is activated each
time the engine is started, this causes too much load to
the engine. The magnetic clutch transmits the power from
the engine to the compressor and activates it when the air
conditioning is ON. Also, it cuts off the power from the
engine to the compressor when the air conditioning is
OFF. Refer to
Compressor in this section for magnetic
clutch repair procedure.
871RX026
Legend
(1) Magnetic Clutch
(2) Magnetic Clutch Connector
(3) Compressor
Condenser
The condenser assembly is located in front of the radiator.
It provides rapid heat transfer from the refrigerant to the
cooling fins.
Also, it functions to cool and liquefy the high-pressure and
high-temperature vapor sent from the compressor by the
radiator fan or outside air.

1A±20
HEATING, VENTILATION AND AIR CONDITIONING (HVAC)
A condenser may malfunction in two ways: it may leak, or
it may be restricted. A condenser restriction will result in
excessive compressor discharge pressure. If a partial
restriction is present, the refrigerant expands after
passing through the restriction.
Thus, ice or frost may form immediately after the
restriction. If air flow through the condenser or radiator is
blocked, high discharge pressures will result. During
normal condenser operation, the refrigerant outlet line will
be slightly cooler than the inlet line.
The vehicle is equipped with the parallel flow type
condenser. A larger thermal transmission area on the
inner surface of the tube allows the radiant heat to
increase and the ventilation resistance to decrease.
The refrigerant line connection has a bolt at the block
joint, for easy servicing.
875R200015
Legend
(1) Pressure Switch
(2) Receiver Drier
(3) Condenser & Receiver Tank Assembly
(4) Condenser Fan
Receiver / Drier
The receiver/drier performs four functions:

As the quantity of refrigerant circulated varies
depending on the refrigeration cycle conditions,
sufficient refrigerant is stored for the refrigeration
cycle to operate smoothly in accordance with
fluctuations in the quantity circulated.

The liquefied refrigerant from the condenser is mixed
with refrigerant gas containing air bubbles. If
refrigerant containing air bubbles. If refrigerant
containing air bubbles is sent to the expansion valve,
the cooling capacity will decrease considerably.
Therefore, the liquid and air bubbles are separated
and only the liquid is sent to the expansion valve.

The receiver/drier utilizes a filter and drier to remove
the dirt and water mixed in the cycling refrigerant.A receiver/drier may fail due to a restriction inside the
body of the unit. A restriction at the inlet to the
receiver/drier will cause high pressure.
Outlet restrictions will be indicated by low pressure and
little or no cooling. An excessively cold receiver/drier
outlet may indicate a restriction.
The receiver/drier of this vehicle is made of aluminum
with a smaller tank. It has a 300cc refrigerant capacity.
The refrigerant line connection has a bolt at the block
joint, for easy servicing.
Triple Pressure Switch (V6, A/T)
Triple pressure switch is installed on the upper part of the
receiver/drier. This switch is constructed with a unitized
type of two switches. One of them is a low and high
pressure switch (Dual pressure switch) to switch ªONº or
ªOFFº the magnetic clutch as a result of irregularly
high±pressure or low pressure of the refrigerant. The
other one is a medium pressure switch (Cycling switch) to
switch ªONº or ªOFFº the condenser fan sensing the
condenser high side pressure.
Compressor
ON
(kPa/psi)OFF
(kPa/psi)
Low-pressure
control206.0+30.0
(29.8+4.3)176.5+24.5
(25.6+3.6)
High-pressure
control2353.6+196.1
(341.3+28.4)2942.0+196.1
(426.6+28.4)
Condenser fanON
(kPa/psi)OFF
(kPa/psi)
Medium-pressure
control1471.0+98.1
(213.3+14.2)1078.7+117.7
(156.4+17.1)
Expansion Valve
This expansion valve is an external pressure type and it is
installed at the evaporator intake port.
The expansion valve converts the high pressure liquid
refrigerant sent from the receiver/drier to a low pressure
liquid refrigerant by forcing it through a tiny port before
sending it to the evaporator.
This type of expansion valve consists of a temperature
sensor, diaphragm, ball valve, ball seat, spring
adjustment screw, etc.
The temperature sensor contacts the evaporator outlet
pipe, and converts changes in temperature to pressure. It
then transmits these to the top chamber of the
diaphragm.
The refrigerant pressure is transmitted to the diaphragm's
bottom chamber through the external equalizing pressure
tube.
The ball valve is connected to the diaphragm. The
opening angle of the expansion valve is determined by
the force acting on the diaphragm and the spring
pressure.

HEATING, VENTILATION AND AIR CONDITIONING (HVAC)
1A±21
The expansion valve regulates the flow rate of the
refrigerant. Accordingly, when a malfunction occurs to
this expansion valve, both discharge and suction
pressure decreases, resulting in insufficient cooling
capacity of the evaporator.
The calibration has been changed to match the
characteristics of HFC-134a.
874R200003
Legend
(1) Expansion Valve
(2) Evaporator Assembly
Evaporator
The evaporator cools and dehumidifies the air before the
air enters the passenger compartment. High-pressure
liquid refrigerant flows through the expansion valve into
the low-pressure area of the evaporator. The heat in the
air passing through the evaporator core is lost to the
cooler surface of the core, thereby cooling the air.
As heat is lost between the air and the evaporator core
surface, moisture in the vehicle condenses on the outside
surface of the evaporator core and is drained off as water.
When the evaporator malfunctions, the trouble will show
up as an inadequate supply of cool air. The cause is
typically a partially plugged core due to dirt, or a
malfunctioning blower motor.The evaporator core with a laminate louver fin is a
single-sided tank type where only one tank is provided
under the core.
874RY00015
Legend
(1) Evaporator Core
(2) Expansion Valve

HEATING, VENTILATION AND AIR CONDITIONING (HVAC)
1A±51
Main Data And Specifications
General Specifications
Heater Unit
Temperature controlReheat air mix system
Capacity4.3 kw (3700 Kcal./hr.)
Air flow280 m
/h
HEATER CORE
TypePlate and corrugate fin
Element dimension167 mm (6.6 in.) y 151 mm (5.9 in.) y 35 mm (1.4 in.)
Radiating areaApprox. 2.4 m
EVAPORATOR ASSEMBLY
Capacity4.8 kw (4100 Kcal./hr.)
Air flow430 m
/hr
EVAPORATOR CORE
TypeAl-laminate louver fin type
Element dimension235 mm (9.3 in.) y 224 mm (8.8 in.) y 60 mm (2.4 in.)
EXPANSION VALVE
TypeInternal pressure equalizer type
CONDENSER
TypeParallel flow type
Radiation performance14.8 kw (12,700 Kcal./hr.)
CONDENSER FAN
Air flow850 m3/h
Fan size
261
RECEIVER/DRIER
TypeAssembly includes triple pressure switch
Internal volume300 cc (10 fl.oz.)
PRESSURE SWITCH
TypeTriple pressure switch
Low pressure control
ON: 206.0+30.0 kPa (29.8+4.3 psi)
OFF: 176.5+19.6 kPa (25.6+2.8 psi)
Medium pressure control
ON: 1471.0+98.1 kPa (213.3+14.2 psi)
OFF: 1078.7+117.7 kPa (156.4+17.7 psi)
High pressure control
ON: 2353.6+196.1 kPa (341.3+28.4 psi)
OFF: 2942.0+196.1 kPa (426.6+28.4 psi)
REFRIGERANT
TypeHFC-134a
Specified amount700 g (1.54 lbs.)

HEATING, VENTILATION AND AIR CONDITIONING (HVAC)
1A±53
Compressor
Service Precaution
WARNING: THIS VEHICLE HAS A SUPPLEMENTAL
RESTRAINT SYSTEM (SRS). REFER TO THE SRS
COMPONENT LOCATION VIEW IN ORDER TO
DETERMINE WHETHER YOU ARE PERFORMING
SERVICE ON OR NEAR THE SRS COMPONENTS OR
THE SRS WIRING. WHEN YOU ARE PERFORMING
SERVICE ON OR NEAR THE SRS COMPONENTS OR
THE SRS WIRING, REFER TO THE SRS ON-VEHICLE
SERVICE INFORMATION. FAILURE TO FOLLOW
CAUTIONS COULD RESULT IN POSSIBLE AIR BAG
DEPLOYMENT, PERSONAL INJURY, OR
OTHERWISE UNNEEDED SRS SYSTEM REPAIRS.
CAUTION: Always use the correct fastener in the
proper location. When you replace a fastener, use
ONLY the exact part number for that application.
ISUZU will call out those fasteners that require a
replacement after removal. ISUZU will also call out
the fasteners that require thread lockers or thread
sealant. UNLESS OTHERWISE SPECIFIED, do not
use supplemental coatings (paints, greases, or other
corrosion inhibitors) on threaded fasteners or
fastener joint interfaces. Generally, such coatings
adversely affect the fastener torque and the joint
clamping force, and may damage the fastener. When
you install fasteners, use the correct tightening
sequence and specifications. Following these
instructions can help you avoid damage to parts and
systems.
General Description
When servicing the compressor, keep dirt or foreign
material from getting on or into the compressor parts and
system. Clean tools and a clean work area are important
for proper service. The compressor connections and the
outside of the compressor should be cleaned before any
ºOn±Vehicleº repair, or before removal of the
compressor. The parts must be kept clean at all times and
any parts to be reassembled should be cleaned with
Trichloroethane, naphtha, kerosene, or equivalent
solvent, and dried with dry air. Use only lint free cloths to
wipe parts.
The operations described below are based on bench
overhaul with compressor removed from the vehicle,
except as noted. They have been prepared in order of
accessibility of the components. When the compressor is
removed from the vehicle for servicing, the oil remaining
in the compressor should be discarded and new
compressor oil added to the compressor.
Compressor malfunction will appear in one of four ways:
noise, seizure, leakage or low discharge pressure.
Resonant compressor noises are not cause for alarm;
however, irregular noise or rattles may indicate broken
parts or excessive clearances due to wear. To check
seizure, de±energize the magnetic clutch and check tosee if the drive plate can be rotated. If rotation is
impossible, the compressor is seized. Low discharge
pressure may be due to a faulty internal seal of the
compressor, or a restriction in the compressor. Low
discharge pressure may also be due to an insufficient
refrigerant charge or a restriction elsewhere in the
system. These possibilities should be checked prior to
servicing the compressor. If the compressor is
inoperative, but is not seized, check to see if current is
being supplied to the magnetic clutch coil terminals.
The compressor oil used in the HFC±134a system
compressor differs from that used in R±12 systems.
Also, compressor oil to be used varies according to the
compressor model. Be sure to avoid mixing two or more
different types of oil.
If the wrong oil is used, lubrication will be poor and the
compressor will seize or malfunction.
DKV-14G Type Compressor
DKV±14G is equipped with five±vane rotary compressor.
These vanes are built into a rotor which is mounted on a
shaft.
When the shaft rotates, the vanes built into the cylinder
block assembly are operated by centrifugal force.
This changes the volume of the spare formed by the rotor
and cylinder, resulting in the intake and compression of
the refrigerant gas. The discharge valve and the valve
stopper, which protects the discharge valve, are built into
the cylinder block assembly. There is no suction valve but
a shaft seal is installed between the shaft and head; a
trigger valve, which applies back pressure to the vanes, is
installed in the cylinder block and a refrigerant gas
temperature sensor is installed in the front head.
The specified quantity of compressor oil is contained in
the compressor to lubricate the various parts using the
refrigerant gas discharge pressure.
871RX002

HEATING, VENTILATION AND AIR CONDITIONING (HVAC)
1A±59
Compressor Oil
Oil Specification

The HFC-134a system requires a synthetic (PAG)
compressor oil whereas the R-12 system requires a
mineral compressor oil. The two oils must never be
mixed.

Compressor (PAG) oil varies according to
compressor model. Be sure to use oil specified for the
model of compressor.

Always use HFC-134a Vane Rotary Type
Compressor Oil (AIPDN Part No.2-90188-301-0)
Handling of Oil

The oil should be free from moisture, dust, metal
powder, etc.

Do not mix with other oil.

The water content in the oil increases when exposed
to the air. After use, seal oil from air immediately.
(HFC-134a Vane Rotary Compressor Oil absorbs
moisture very easily.)

The compressor oil must be stored in steel
containers, not in plastic containers.
Compressor Oil Check
The oil used to lubricate the compressor is circulating with
the refrigerant.
Whenever replacing any component of the system or a
large amount of gas leakage occurs, add oil to maintain
the original amount of oil.
Oil Capacity
Capacity total in system: 150cc (5.0 fl.oz)
Compressor (Service parts) charging amount:
150 cc (5.0 fl.oz)
Checking and Adjusting Oil Quantity
for Used Compressor
1. Perform oil return operation. Refer to Oil Return
Operation in this section.
2. Discharge and recover refrigerant and remove the
compressor.
3. Drain the compressor oil and measure the extracted
oil with a measuring cylinder.
4. If the amount of oil drained is much less than 90 cc
(3.0 fl. oz.), some refrigerant may have leaked out.
Conduct a leak tests on the connections of each
system, and if necessary, repair or replace faulty
parts.
5. Check the compressor oil contamination. (Refer to
Contamination of Compressor Oil in this section.)
6. Adjust the oil level following the next procedure
below.(Charging Amount)
(Collected Amount)
more than 90cc (3.0
fl.oz)same as collected
amount
less than 90 cc (3.0 fl.oz)90cc (3.0 fl.oz)
7. Install the compressor, then evacuate, charge and
perform the oil return operation.
8. Check system operation.
When it is impossible to preform oil return operation,
the compressor oil should be checked in the
following order:
1. Discharge and recover refrigerant and remove the
compressor.
2. Drain the compressor oil and measure the extracted
oil with a measuring cylinder.
3. Check the oil for contamination.
4. If more than 90 cc (3.0 fl. oz.) of oil is extracted from
the compressor, supply the same amount of oil to the
compressor to be installed.
5. If the amount of oil extracted is less than 90 cc (3.0 fl.
oz.), recheck the compressor oil in the following
order.
6. Supply 90 cc (3.0 fl. oz.) of oil to the compressor and
install it onto the vehicle.
7. Evacuate and recharge with the proper amount of
refrigerant.
8. Perform the oil return operation.
9. Remove the compressor and recheck the amount of
oil.
10. Adjust the compressor oil, if necessary.
(Collected Amount)
(Charging Amount)
more than 90 cc (3.0
fl.oz)same as collected
amount
less than 90 cc (3.0 fl.oz)90 cc (3.0 fl.oz)

HEATING, VENTILATION AND AIR CONDITIONING (HVAC)
1A±61
Main Data and Specifications
General Specifications
COMPRESSOR
ModelDKV-14G
TypeVane rotary type
Number of vanes5
Rotor diameter64 mm (2.52 in.)
Stroke8.75 mm (0.34 in.)
Displacement140 cc (47.3 fl.oz.)
Maximum speed7,000 rpm (up to 8,400 rpm)
Direction of rotationClockwise (Front-side view)
Lubrication systemPressure differential type
LubricantR-134a Vane Rotary Type Compressor Oil
(AIPDN Part No.2-90188-301-0)
150 cc (5.0 fl.oz.)
RefrigerantRefrigerant-134a (R-134a), 700 g (1.54 lbs.)
Shaft sealLip type
Weight3.5 kg
MAGNETIC CLUTCH
TypeElectromagnetic single-plate dry clutch
Rated voltage12 Volts D.C.
Current consumption3.7 A
Starting torque49 N´m (36 lb´ft)
Direction of rotationClockwise (Front-side view)
Weight3.0 kg (6.6 lbs.)