2007 ISUZU KB P190 ECO mode

1-32 HEATER AND AIR CONDITIONING

Insert nut into union. First tighten nut by hand as much as
possible. Then, tighten nut to specified torque.
(Refer to "Special Parts Fixing Nuts and Bolts" in this section)


LEAK AT REFRIGERANT LINE
CONNECTIONS

1) Check the torque on the refrigerant line fitting and, if too
loose, tighten to the specified torque.
• Use two wrenches to prevent twisting and damage to the
Line.
• Do not over tighten.
2) Perform a leak test on the refrigerant line fitting.
3) If the leak is still present, discharge and recover the refrigerant from the system.
4) Replace the O-rings. • O-rings cannot be reused. Always replace with new
ones.


• Be sure to apply specified compressor oil to the new O-
rings.


5) Retighten the refrigerant line fitting to the specified torque.
• Use two wrenches to prevent twisting and damage to the
line.
6) Evacuate, charge and retest the system.

LEAK IN THE HOSE
If the compressor inlet or outlet hose is leaking, the entire hose
must be replaced. Refrigerant hose must not be cut or spliced
for repair.
1) Locate the leak.
2) Discharge and recover the refrigerant.
3) Remove the hose assembly. • Cap the open connections at once.
4) Connect the new hose assembly. • Use two wrenches to prevent twisting or damage to the
hose fitting.


• Tighten the hose fitting to the specified torque.
5) Evacuate, charge and test the system.

COMPRESSOR LEAKS
If leaks are located around the compressor shaft seal or shell,
replace or repair the compressor.

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ISUZU KB P190 2007

HEATER AND AIR CONDITIONING 1-33
RECOVERY, RECYCLING, EVACUATION
AND CHARGING
Handling Refrigerant-134a (HFC-134a)
Air conditioning systems contain HFC-134a.
This is a chemical mixture, which requires special handling
procedures to avoid personal injury.
• Always wear safety goggles and protective gloves.
• Always work in a well-ventilated area. Do not weld or steam
clean on or near any vehicle-installed air conditioning lines
or components.
• If HFC-134a should come in contact with any part of the
body, flush the exposed area with cold water and
immediately seek medical help.
• If it is necessary to transport or carry any container of HFC-
134a in a vehicle, do not carry it in the passenger
compartment.
• If it is necessary to fill a small HFC-134a container from a
large one, never fill the container completely. Space should
always be allowed above the liquid for expansion.
• Keep HFC-134a containers stored below 40 °C (104 °F).


WARNING
•
••
•
SHOULD HFC-134a CONTACT YOUR EYE(S), CONSULT
A DOCTOR IMMEDIATELY.
•
••
•
DO NOT RUB THE AFFECTED EYE(S). INSTEAD,
SPLASH QUANTITIES OF FRESH COLD WATER OVER
THE AFFECTED AREA TO GRADUALLY RAISE THE
TEMPERATURE OF THE REFRIGERANT ABOVE THE
FREEZING POINT.
•
••
•
OBTAIN PROPER MEDICAL TREATMENT AS SOON AS
POSSIBLE. SHOULD THE HFC-134a TOUCH THE SKIN,
THE INJURY MUST BE TREATED THE SAME AS SKIN
WHICH HAS BEEN FROSTBITTEN OR FROZEN.

F06R300012


REFRIGERANT RECOVERY
The refrigerant must be discharged and recovered by using
ACR4 (HFC-134a Refrigerant Recovery/Recycling/Recharging/
System) or equivalent before removing or installing air
conditioning parts.
ACR
4 (115V 60Hz) :5-8840-0629-0 (J-39500-A)
ACR4 (220-240V 50/60Hz)
: 5-8840-0630-0 (J-39500-220A)
ACR
4 (220-240V 50/60Hz Australian model)
: 5-8840-0631-0 (J-39500-220ANZ)
1) Connect the high and low charging hoses of the ACR
4 (or
equivalent) as shown.
2) Recover the refrigerant by following the ACR
4
Manufacturer's Instructions.
3) W hen a part is removed, put a cap or a plug on the connecting portion so that dust, dirt or moisture cannot get
into it.

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ISUZU KB P190 2007

1-34 HEATER AND AIR CONDITIONING

REFRIGERANT RECYCLING
Recycle the refrigerant recovered by ACR4 or equivalent.
For the details of the actual operation, follow the steps in the
ACR
4 Manufacturer's Instructions.
ACR4 (115V 60Hz) :5-8840-0629-0 (J-39500-A)
ACR4 (220-240V 50/60Hz)
: 5-8840-0630-0 (J-39500-220A)
ACR
4 (220-240V 50/60Hz Australian model)
: 5-8840-0631-0 (J-39500-220ANZ)

F06R300014


EVACUATION OF THE REFRIGERANT
SYSTEM
NOTE:
Explained below is a method using a vacuum pump. Refer
to the ACR
4 (or equivalent) Manufacturer's Instructions
when evacuating the system with ACR4 (or equivalent).

Air and moisture in the refrigerant will cause problems in the air
conditioning system.
Therefore, before charging the refrigerant, be sure to evacuate
air and moisture thoroughly from the system.
1) Connect the gauge manifold. •
••
•
High-pressure valve (HI) - Discharge-side
•
••
•
Low-pressure valve (LOW ) - Suction-side
2) Discharge and recover the refrigerant.
3) Connect the center hose of the gauge manifold set to the vacuum pump inlet.
4) Operate the vacuum pump, open shutoff valve and then open both hand valves.
5) W hen the low-pressure gauge indicates approx. 100kPa (750 mmHg/30 inHg), continue the evacuation for 5 minutes
or more.
6) Close both hand valves and stop the vacuum pump.


7) Check to ensure that the pressure does not change after 10
minutes or more. •
••
•
If the pressure changes, check the system for leaks.
•
••
•
If leaks occur, retighten the refrigerant line connections
and repeat the evacuation steps.
8) If no leaks are found, again operate the vacuum pump for 20 minutes or more. After confirming that the gauge
manifold pressure is at 100 kPa (750 mmHg/30 inHg), close
both hand valves.
9) Close positive shutoff valve.
Stop the vacuum pump and disconnect the center hose from the vacuum pump.


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ISUZU KB P190 2007

HEATER AND AIR CONDITIONING 1-35
CHARGING THE REFRIGERANT SYSTEM
There are various methods of charging refrigerant into the air
conditioning system.
These include using the ACR
4 (HFC-134a Refrigerant
Recovery/ Recycling/Recharging/System) or equivalent and
direct charging with a manifold gauge charging station.
ACR
4 (115V 60Hz) : 5-8840-0629-0 (J-39500-A)
ACR4 (220-240V 50/60Hz)
: 5-8840-0630-0 (J-39500-220A)
ACR
4 (220-240V 50/60Hz Australian model)
: 5-8840-0631-0 (J-39500-220ANZ)
F06R300012
Charging procedure
•
••
•
ACR4 (or equivalent) method
For the charging of refrigerant recovered by ACR4, follow the
Manufacturer's Instruction.


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HEATER AND AIR CONDITIONING 1-37
refrigerant container.


1) Make sure the evacuation process is correctly completed.
2) Connect the center-hose of the manifold gauge to the refrigerant container. •
••
•
Turn the charge valve handle counterclockwise to purge
to the charging line and purge any air exiting in the
center-hose of the manifold gauge.
3) Open the low-pressure hand valve and charge the refrigerant about 200 g (0.44 lbs.). •
••
•
Make sure the high-pressure hand valve is closed.
•
••
•
Avoid charging the refrigerant by turning the refrigerant
container upside down.
4) Close the low-pressure hand valve of the manifold gauge. •
••
•
Check to ensure that the degree of pressure does not
change.
5) Check the refrigerant leaks by using a HFC-134a leak detector. •
••
•
If a leak occurs, repair the leak connection, and start all
over again from the first step of evacuation.
6) If no leaks are found, open the low-pressure hand valve of the manifold gauge. Then continue charging refrigerant to
the system. •
••
•
W hen charging the system becomes difficult:
(1) Run the engine at Idling and close the all vehicle doors.
(2) A/C switch is "ON".
(3) Set the fan control knob (fan switch) to its highest position.
(4) Set air source selector lever to “RECIRC”



WARNING
BE ABSOLUTELY SURE NOT TO OPEN THE HIGH-
PRESSURE HAND VALVE. SHOULD THE HIGH-
PRESSURE HAND VALVE BE OPENED, THE HIGH-
PRESSURE REFRIGERANT GAS WOULD FLOW
BACKWARD, AND THIS MAY CAUSE THE REFRIGERANT
CONTAINER TO BURST.
7) W hen the refrigerant container is emptied, use the following procedure to replace it with a new refrigerant container.
(1) Close the low-pressure hand valve.
(2) Raise the needle upward and remove the charge valve.
(3) Reinstall the charge valve to the new refrigerant container.
(4) Purge any air existing in the center hose of the manifold gauge.






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HEATER AND AIR CONDITIONING 1-39
Reading Sight Glass

High and low
pressure pipe
temperature The high pressure
pipe is hot and the
low pressure pipe
is cold. There is a
distinct difference
in temperature
between them. The high pressure
pipe is warm and
the low pressure
pipe is cool. There
is no great
difference in
temperature
between them. There is little
difference in
temperature
between the high
pressure pipe and
the low pressure
pipe. The high pressure
pipe is hot and the
low pressure pipe
is slightly warm.
There is a
difference in
temperature
between them.
Sight glass
condition Almost transparent.
A flow of bubbles
can be seen, but
they disappear
when the throttle is
opened.

A flow of bubbles
always can be
seen. It appears
sometimes
transparent, and
sometimes frothy.
Something like fog
faintly can be seen.
Even at idle with
the fan at "HI" (with
the window fully
open), the bubbles
cannot be seen.



Air conditioning
cycle condition
OK NG
(Not enough refrigerant) NG
(Almost no
refrigerant) NG
(Too much
refrigerant)

The sight glass provides accurate diagnosis only under the following conditions.
If the vehicle can be tested under these conditions, check the sight glass appearance and compare to the chart.
* Engine speed Idling
* A/C switch "ON"
* Blower fan operating at highest speed
* Air source selector lever at "RECIRC"
* Temperature control knob at coldest position
* Ambient temperature below 35 °C (95 °F) and humidity below 70% (See NOTE 1)
* High side pressure less than 1470 kPa (15 kg/cm
2 / 213 psi) (See NOTE 2)

NOTE 1
If the vehicle cannot be moved to a testing location that meets these specifications, then the sight glass cannot be
used for diagnosis. You must discharge and recover the refrigerant, then recharge the system with the specified
amount of refrigerant. Then continue checking the system performance.

NOTE 2
If the high side pressure is greater than stated, the sight glass cannot be used for diagnosis. You must discharge
and recover the refrigerant, then recharge the system with the specified amount of refrigerant. Then continue
checking system performance.



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HEATER AND AIR CONDITIONING 1-53
Checking and Adjusting for Compressor
Replacement
180 cm3 (5.07 lmp fl oz) of oil is charged in compressor
(service parts). So it is necessary to drain the proper amount
of oil from the new compressor.
1) Perform oil return operation.
2) Discharge refrigerant and remove the compressor.
3) Drain the compressor oil and measure the extracted oil.
4) Check the compressor oil for contamination.
5) Adjust oil level as required.
Amount of oil drained
From used compressor Draining amount of oil
From new compressor
less than
90 cm
3 (2.53 lmp fl oz) Some as drained
amount
more than
90 cm
3 (2.53 lmp fl oz) 90 cm
3 (2.53 lmp fl oz)

6) Evacuate, charge and perform oil return operation.
7) Check system operation.


CONTAMINATION OF COMPRESSOR OIL
Unlike engine oil, no cleaning agent is added to the
compressor oil. Even is the compressor runs for a long period
of time (approximately 1 season), the oil never becomes
contaminated as long as there is nothing wrong with the
compressor or its method of use.
Inspect the extracted oil for any of the following
conditions:
• The capacity of the oil has increased.
• The oil has changed color to red.
• Foreign substances, metal powder, etc., are present in the
oil.
If any of these conditions exists, compressor oil is
contaminated. Whenever contaminated compressor oil is
discovered, the receiver/drier must be replaced.


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HEATER AND AIR CONDITIONING 1-89
AIR CONDITIONING CYCLE TROUBLESHOOTING

TROUBLE POSSIBLE CAUSE CORRECTION
1. Magnetic clutch does not run
•
Refer to “MAGNETIC CLUTCH”
troubleshooting in this section
2. Compressor is not rotating properly
• Drive belt loosened or broken •
Adjust the drive belt to the specified
tension or replace the drive belt
• Magnetic clutch face is not clean and
slips •
Clean the magnetic clutch face or replace

• Incorrect clearance between magnetic
drive plate and pulley •
Adjust the clearance (Refer to
“COMPRESSOR OVERHAUL”)
• Compressor oil leaks from shaft seal or
shell •
Replace the compressor

• Compressor seized • Replace the compressor
3. Insufficient or excessive charge of
refrigerant •
Discharge and recover refrigerant.
Recharge to specified amount.
4. Leaks in the refrigerant system


•
Check refrigerant system for leaks and
repair as necessary
Discharge and recover refrigerant.
Recharge to specified amount.
5. Condenser clogged or insufficient radiation

•
Clean the condenser or replace as
necessary
• Check radiator or condenser fan function
6. Temperature control link unit of the heater
unit defective •
Repair the link unit
7. Unsteady operation due to foreign
substance in expansion valve •
Replace the expansion valve

No cooling or
insufficient
cooling
8. Poor operation of electronic thermostat
•
Check electronic thermostat and replace
as necessary
1. Evaporator clogged or frosted
•
Check evaporator core and replace or
clean the core
2. Air leaking from cooling unit or air duct
•
Check evaporator and duct connection,
then repair as necessary
Insufficient
velocity
of cooling air
3. Blower motor does not rotate properly
• Refer to “FAN CONTROL KNOB (FAN
SW ITCH)” troubleshooting in this section

* For the execution of the charging and discharging operation in the table above, refer to the “RECOVERY,
RECYCLING, EVACUATING AND CHARGING” in this section.



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