Komatsu 930E-2, Shop Manual

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6. Start the recovery process by operating the equip-
ment as per the manufacturer’s instructions.
7. Continue extraction until a vacuum exists in the AC
system.
8. If an abnormal amount of time elapses after the
system reaches 0 psi and does not drop steadily
into the vacuum range, close the manifold valves
and check the system pressure. If it rises to 0 psi
and stops, there is a major leak.
9. Check the system pressure after the recovery
equipment stops. After five minutes, system pres-
sure should not rise above “0” gauge pressure. If
the pressure continues to rise, restart and begin
the recovery sequence again. This cycle should
continue until the system is void of refrigerant.
10. Check the sight glass oil level to determine the
amount of oil that needs to be replaced. (The
amount of oil that was lost during the recovery
cycle must be replaced back into the system).
11. Mark the cylinder with a RECOVERED (red) mag-
netic label to reduce the chance of charging a
system with contaminated refrigerant. Record the
amount of refrigerant recovered.
Performing the Recycling Procedure
The recovered refrigerant contained in the cylinder
must undergo the recycle procedure before it can be
reused. The recycle or clean mode is a continuous loop
design and cleans the refrigerant rapidly. Follow equip-
ment manufacturer’s instructions for this procedure.
Evacuating and Charging the AC System
Evacuate the system once the air conditioner compo-
nents are repaired or replacement parts are secured,
and the AC system is reassembled. Evacuation re-
moves air and moisture from the system. Then, the AC
system is ready for the charging process, which adds
new refrigerant to the system.
Evacuating the System
1. Attach the high and low side hoses to the appro-
priate connections.
2. Start the vacuum pump and run it for five minutes.
3. Check the gauge readings for five minutes. If the
gauge needle moves up, the system is not sealed.
The vacuum that was just created did not hold, air
and moisture are being sucked into the system by
that same vacuum.
4. Tighten any loose connections. Re-start the pump,
and open the hand valves on the gauges again.
Repeat the vacuum test.
5. If the leak has been repaired, run the vacuum
pump for at least an hour to remove any moisture
from the system.
The moisture must turn to gas before the pump can pull
it out. The moisture takes time to boil away, so that it
can be drawn out of the system. The vacuum pump can
draw most of the air out quickly, but a deep vacuum
requires more time; the deeper the vacuum the more
time required.
Charging the AC System
When adding a full charge of refrigerant, it is possible
to put it in as a gas or as a liquid. Adding refrigerant as
a liquid is faster but can damage the compressor if not
done correctly. The procedure used, and where the
refrigerant is added in the AC system makes a differ-
ence. When using refrigerant as a liquid, never add
more than two thirds of system requirements as a
liquid. Finish charging the system using gas.
M9-14 Air Conditioning System M09010 6/97
for HFC 134a Refrigerant