Stabilizing The Ac System; Adding Refrigerant And Stabilizing The System; Performing The Recovery Cycle; Draining The Oil From The Previous Recovery Cycle - Komatsu 930E-2 Shop Manual

5. When the gauges show a normal reading, close
the hand valve on the refrigerant container.

Stabilizing the AC System

During this stabilization period, do not open hand
valves on manifold for any reason. Equipment dam-
age and personal injury may result.
1. Start the engine and return to an idle speed of 1200
to 1500 RPM. Turn on the air conditioner.
2. After a performance check of the control functions,
blower speeds and air flow, set the AC system
controls to maximum cooling and blower speed
on high. All windows must be closed. If the cab
temperature is hot, open the windows long
enough to allow the hot air to move out of the cab.
3. Run the engine and air conditioner about 5 minutes
for the system to stabilize.
4. If the humidity is high it will be necessary to place
a fan in front of the AC condenser to help the air
flow across the condenser. This helps to stabilize
the system by simulating normal operating condi-
tions.
5. It is then possible to observe the gauge readings
and the temperature coming out of the air ducts
with a thermometer.
NOTE: If low refrigerant is indicated by lower than
normal pressure readings, add refrigerant to enable
adequate system testing.

Adding Refrigerant and Stabilizing the System

(with a recovery/recycling station)
When using a recovery/recycling station the procedure
is the same as previously described. The difference is
that instead of just opening the refrigerant container
the refrigerant should be added 0.5 to 1 pound at a
time. After each instance of adding the refrigerant,
pause long enough to observe the gauge reading to
determine if the system is full. Again using the pres-
sures that were mentioned above.
M09010 6/97
Do not open high side hand valve. High side sys-
tem pressure is greater than refrigerant container.
Serious personal injury may result if the container
explodes.
Use hand valve to regulate low side reading during
charging. DO NOT EXCEED 40 psi maximum.
Exceeding this pressure may cause compressor
failure.
RECOVERING AND RECYCLING THE
REFRIGERANT

Draining the Oil from the Previous Recovery Cycle

1. Place the power switch and the controller on the
recovery unit in the OFF position.
2. Plug in the recovery station to the correct power
source.
3. Drain the recovered oil through the valve marked
OIL DRAIN on the front of the machine.
4. Place the controller knob in the ON position. The
low pressure gauge will show a rise.
5. Immediately switch to the OFF position and allow
the pressure to stabilize. If the pressure does not
rise to between 5 psi and 10 psi, switch the con-
troller ON and OFF again.
6. When the pressure reaches 5 to 10 psi, open the
OIL DRAIN valve, collect oil in an appropriate
container, and dispose of container as indicated
by local, state or Federal Regulation. THE OIL IS
NOT REUSABLE, DUE TO CONTAMINANTS AB-
SORBED DURING ITS PREVIOUS USE.

Performing the Recovery Cycle

1. Be sure the equipment being used is designed for
the refrigerant you intend to recover.
2. Observe the sight glass oil level. Having drained
it, it should be zero.
3. Check the cylinder refrigerant level before begin-
ning recovery to make sure you have enough
capacity.
4. Confirm that all shut-off valves are closed before
connecting to the AC system.
5. Attach the appropriate hoses to the system being
recovered.
Air Conditioning System
for HFC 134a Refrigerant
M9-13