Komatsu 830E-AC Shop Manual page 944

Installing Manifold Gauge Set
Before attempting to service the air conditioning sys-
tem, a visual inspection of both the engine and A/C
system components is recommended. Particular
attention should be given to the belts, hoses, tubing
and all attaching hardware as well as the radiator
cap, fan clutch, and thermostat. Inspect both the con-
denser and the radiator for any obstructions or poten-
tial contamination. Minimize all the possibilities for
error or malfunction of components in the air condi-
tioning system.
Shut off engine. DO NOT attempt to connect ser-
vice equipment when the engine is running.
1. Be sure all valves on the manifold are closed all
the way (turn them clockwise).
2. Check the hose connections on the manifold for
tightness.
3. Locate the low and high side system service fit-
tings and remove their protective caps.
FIGURE 4-11. SERVICE HOSE HOOK-UP
N4-18
4. Connect the two service hoses from the mani-
fold to the correct service valves on the com-
pressor and accumulator, as shown in Figure 4-
11. (High side to compressor discharge valve
and low side to accumulator.) Do not open the
service valves at this time.
This gauge hook-up process will be the same,
regardless of the gauge set being installed. Whether
it is a recovery station or individual gauges, the con-
nections are the same. The procedures performed
next will vary depending what type of equipment is
being used. If a recovery/recycling station is being
used, complete servicing can be accomplished.
Using only a set of gauges will limit the servicing to
only adding refrigerant or observing pressures.
Purging Air From Service Hoses
The purpose of this procedure is to remove all the air
trapped in the hoses prior to actual system testing.
Environmental regulations require that all service
hoses have a shutoff valve within 12 inches of the
service end. These valves are required to ensure
only a minimal amount of refrigerant is lost to the
atmosphere. R-134a gauge sets have a combination
quick disconnect and shutoff valve on the high and
low sides. The center hose also requires a valve.
The initial purging is best accomplished when con-
nected to recovery or recycle equipment. With the
center hose connected to the recovery station, ser-
vice hoses connected to the high and low sides of the
system, we can begin the purging. The manifold
valves and service valves should be closed. Activat-
ing the vacuum pump will now pull any air or mois-
ture out of the center hose. This will require only a
few minutes of time. The hose is the only area that is
being placed in a vacuum and this will not require a
lengthy process. Closing the valve will then insure
the hose is purged. It is now safe to open the other
manifold valves.
Operator Comfort 10/06 N04031