refrigerant type ISUZU TROOPER 1995 Workshop Manual

The refrigeration cycle includes the following four
processes as the refrigerant changes repeatedly
from liquid to gas and back to liquid while circulat­
ing.
EVAPORATION
The refrigerant is changed from a liquid to a gas in­
side
the evaporator. The refrigerant mist that enters
the evaporator vaporizes readily. The liquid refrige­
rant removes
the required quantity of heat (latent
heat of vaporization) from the air around the evap­
orator 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 and 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 tempera­
tures close to ooc (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.
AIR CONDITIONING 1 B -3
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
It 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. And it pumps refrigerant and
refrigerant
oil through the air conditioning system.
This vehicle is equipped with five-vane rotary com­
pressor.
The
thermo sensor is installed to the front head of
the compressor to protect it by stopping its
operation when the refrigerant gas is insufficient or
when the temperature is abnormally high.
• OFF ...... 160 ±soc (320.0 ± 9.0°F)
• ON
...... 135 ±soc (27S.O ± 9.0°F)
The specified amount of the compressor oil is 1SOcc
(S.O 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 ac­
tivated 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 com­
pressor 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".
(Magnetic clutch repair procedure can be found in
Section 1 D.)

1 B - 4 AIR CONDITIONING
Compressor
Thermosensor
Magnetic clutch
Fig. 18-2
CONDENSER
The condenser assembly is located in front of the
radiator. It carries the refrigerant and cooling fins to
provide rapid transfer of heat.
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.
A condenser
may malfunction in two ways: it may
leak, or it may be restricted. A condenser restric­
tion 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 from immediately after the
restriction. If air flow through the condenser or
radiator is blocked, high discharge pressures will
result. During normal condenser operation, the re­
frigerant 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.
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 refrigera­
tion 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 bub­
bles. 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 dryer to
remove the dirt and water mixed in the cycling
refrigerant.
• The sight glass, installed atop the receiver/
drier, show the state of the refrigerant.
A receiver/drier may fail due to a restriction inside
the body of the unit. A restriction at inlet to the re­
ceiver/drier
will cause high pressures.
Outlet restrictions will be indicated by low pressure
and
little or no cooling. An excessively cold re­
ceiver/drier
outlet may indicate a restriction.
The receiver/drier
of this vehicle is made of alu­
minum with a smaller tank. It has 300 cc refrigerant
capacity.
The
refrigerant line connection has a bolt at the
block joint, for easy servicing.
PRESSURE SWITCH
The pressure switch (Dual pressure switch) is in­
stalled on the upper part of the receiver/drier, to
detect excessively high pressure (high pressure
switch) and prevent compressor seizure due to the
refrigerant leaking (low pressure switch), so that the
compressor is able to turned "ON" or "OFF".
The pressure characteristics of HFC-134a refrigerant
differ from those of R-12. Thus, the pressure switch
operation for HFC-134a systems has been changed
from R-12.
• Compressor ON · OFF (kPa/psi)
Low-pressure control
ON: 186.3 ± 29.4 (27.0 ± 4.3)
OFF: 176.5 ± 19.6 (25.6 ± 2.8)
High-pressure
control
ON: 2059.4 ± 196.1 (341.3 ± 28.4)
OFF: 2942.0 ± 196.1 (426.6 ± 28.4)

Fig. 18-3
EXPANSION VALVE
This expansion valve is 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 tempera­
ture 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 dia­
phragms 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.
The
expansion valve regulates the flow rate of the
refrigerant. Accordingly, when a malfunction occurs
to this expansion valve, both discharge and suction
pressures
get low, resulting in insufficient cooling
capacity of the evaporator.
The
calibration has been changed to match the
characteristics of HFC-134a.
AIR CONDITIONING 1 B - 5
Fig. 18-4
EVAPORATOR
The evaporator cools and dehumidifies the air
before the air enters the vehicle. 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 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.
Evaporator core
=
Fig. 18-5

AIR CONDITIONING 1 B -33
MAIN DATA AND SPECIFICATIONS
GENERAL SPECIFICATIONS
HEATER UNIT
Temperature control Reheat air mix system
Capacity
(Kcal./hr.) 3,700
Air flow (m3/hr.) 280
HEATER CORE
Type
Fin & tube type
Element dimension mm (in.) 161 (6.3) X 163 (6.4) X 45 (1.8)
Radiating area
m2 Approx. 2.1
EVAPORATOR ASSEMBLY
Capacity (Kcal./hr.)
4,200
Air flow (m3/hr.) 470
EVAPORATOR
CORE
Type Al-laminate louver fin type
Element dimension mm(in.) 235 (9.3) X 224 (8.8) X 7 4 (2.9)
EXPANSION VALVE
Type
External pressure equalizer type
THERMOSTAT SWITCH
Type oc (F) Electronic thermostat
OFF: Below 3.5 ± 0.5 (38.3 ± 0.9)
ON:
Above 5.0 ± 0.5 (41.0 ± 0.9)
CONDENSER
Type Parallel flow
Radiation performance (Kcal./hr.) 11,200
RECEIVER/DRIER
Type Assembly includes sight glass with dual
pressure switch
Internal volume cc (fl. oz.) 300 (10)
PRESSURE SWITCH
Type Dual pressure switch
kPa (psi) • Low pressure control
ON:
186.3 ± 29.4 (27.0 ± 4.3)
OFF: 176.5 ± 19.6 (25.6 ± 2.8)
• High pressure control
ON: 2059.4
± 196.1 (341.3 ± 28.4)
OFF: 2942.0 ± 196.1 (426.6 ± 28.4)
REFRIGERANT
Type
HFC-134a
Specified
amount g (lbs.) 750 (1.65)

COMPRESSOR OVERHAUL 1 D - 1
SECTION 10
COMPRESSOR OVERHAUL
CONTENTS
General Description . . . . . . . . . . . . . . . . . . . . . 1 D-1
Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
D-2
General Information . . . . . . . . . . . . . . . . . . . . 1 D-3
Compressor Oil . . . . . . . . . . . . . . . . . . . . . . 1 D-3
Service Procedures . . . . . . . . . . . . . . . . . . . . . 1D-5
Magnetic Clutch Assembly . . . . . . . . . . . . . 1 D-5
Main Data and Specifications . . . . . . . . . . . . . 1 D-8
General Specifications . . . . . . . . . . . . . . . . . 1 D-8
Torque Specifications . . . . . . . . . . . . . . . . . 1 D-8
Special Tools . . . . . . . . . . . . . . . . . . . . . . . . . . 1D-9
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 "On-Vehicle" 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 Trichloro­
ethane, 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.
Magnetic clutch assembly repair procedures require
that the system be discharged of refrigerant. (Refer
to Section 1 B for "REFRIGERANT RECOVERY".)
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 to see if the drive plate
can be rotated.
If rotation is impossible, the com­
pressor is seized. Low discharge pressure may be
due to a faulty internal seal of the compressor, or a
restriction in the compressor.
Low discharge pres­
sure
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.
This vehicle is equipped with five-vane rotary com­
pressor.
The
compressor has vanes built into a rotor which is
mounted on a shaft.
When the shaft rotates, the vanes built into the
cylinder block assembly are opened by centrifugal
force.
This changes the volume of the space 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.
The thermo sensor is installed to the front head of
the compressor to protect it by stopping its
operation when the refrigerant gas is insufficient or
when the temperature get abnormally high.
•OFF ..... 160 ±soc (320.0 ± 9.0°F)
•ON ..... 135 ±soc (275.0 ± 9.0°F)
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 specified
amount of the compressor oil is
150cc (5.0 fl.oz.).

COMPRESSOR OVERHAUL 10-3
GENERAL INFORMATION
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 com­
pressor model. Be sure to use oil specified for
the model of compressor.
• Always use HFC-134a Vane Rotary Type Com­
pressor 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 circul­
ating 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 15 0cc (5
·0
fl.oz.)
Checking and Adjusting 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 (Fig. 1 D-
2).
Fig. 1D-2
4. If the amount of oil drained is much less than
90cc (3.0 fl.oz.), some refrigerant may have
leaked out. Conduct leak tests on connections of
each system, and if necessary, repair or replace
faulty parts.
5. Check the compressor oil for contamination.
(Refer to "Contamination of Compressor Oil" in
this section.)
6. Adjust oil level following the procedure below
(Fig. 1 D-3).
Collected Amount
more than 90cc
(3.0 fl.oz.)
Charging Amount
same as collected amount
less than 90cc (3.0 fl.oz.) 90cc (3.0 fl.oz.)
7. Install the compressor, then evacuate, charge
and
perform oil return operation.
8. Check system operation.
When it is impossible to perform oil return oper­
ation, 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 90cc (3.0 fl.oz.) of oil is extracted
from the compressor, supply same amount of
oil to the compressor to be installed.
If
the amount of oil extracted is less than 90cc
(3.0 fl.oz.),
recheck the compressor oil in the
following order:
5. Supply 90cc (3.0 fl.oz.) of oil to the compressor
and install it onto the vehicle.

10-8 COMPRESSOR OVERHAUL
MAIN DATA AND SPECIFICATIONS
GENERAL SPECIFICATIONS
COMPRESSOR
Model
Type
Number of vanes
Rotor
diameter
Stroke
Displacement
Maximum speed
Direction
of rotation
Lubrication system
Lubricant
Refrigerant
Shaft seal
Weight
MAGNETIC CLUTCH
Type
Rated voltage
Current consumption
Starting torque
Direction of rotation
Weight
TORQUE SPECIFICATIONS
mm (in)
mm (in)
cc/Rev. (cu. in/Rev)
(rpm)
cc (fl.oz)
g (lb)
kg (lb)
(A)
N·m (lb·ft)
kg (lb)
Fig. 1D-16 DKV-14D
Vane
rotary type
5 64 (2.52)
8.75
(0.34)
140
(8.54)
7,000 (up to 8,400)
Clockwise
(Front-side view)
Pressure
differential type
HFC-134a Vane Rotary Compressor Oil
(AIPDN
Part No. 2-90188-301-0)
150 (5.0)
HFC-134a, 750 (1.65)
Lip
type
3.6 (7.94)
Electromagnetic single-plate dry clutch
12 Volts D.C.
3.7
49 (36)
Clockwise (Front-side view)
2.2 (4.9)
N·m (lb·in)
•