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WA900-3EO
COMMISSIONING
STEP 1.
If a new system, evacuate for a minimum
period of four hours. If the system has been
opened to undergo repairs an evacuation
period of one hour should be sufficient pro-
vided connections have been capped during
the repair period. The filter/drier should be
changed.
Early in the evacuation period close valves
on the gauge set for several minutes to
see if gauge needles remain stationary. If
they do it is an indication that the system is
leak free; if they move back towards zero a
leak is indicated and leak testing procedure
should be implemented and the leak cor-
rected
(please see
Nitrogen Leak Testing
for
general instructions).
STEP 2
At the end of the evacuation period partially
charge the system with R134a vapour into
the compressor suction service valve and
recheck the whole system for leaks
(please
see
System Evacuation
for further details).
STEP 3
Turn the thermostat to its coldest setting: run
the engine at fast idling speed and charge
the system; do not use liquid in the charging
process
(please see
System Charging
for
further details).
STEP 4
With the lid of the unit closed, run engine up
to maximum rpm.
STEP 5
Note compressor discharge and suction
pressures and check the feel and condition
of the compressor suction service valve.
STEP 6
If the discharge pressure is within the 820 to
1300 kPa (120 to 190 Psi) range, the suction
pressure should be in the 70 to 138 kPa (10
to 20 Psi) range when ambient temperature
is above 21
o
C and the cabin temperature is
down to comfort conditions.
STEP 7
At higher or lower ambient temperatures,
the gauge reading will vary accordingly. (In
winter conditions, position the vehicle in the
sun with maximum solar penetration of cab
glass; blank or partially blank fan intake
using sheet metal or cardboard to raise
discharge pressure to nominal 820 kPa (120
Psi).
STEP 8
To provide adequate compressor cooling
and maximum evaporator coil performance,
gas returning to compressor should be cold
and the suction service valve cold and
sweaty but NOT icing.
STEP 9
When the thermostat is set to the minimum
setting, it is necessary to ensue the evapo-
rator cannot ice up under low return air tem-
peratures, on high or low fans and with the
compressor running at maximum speed.
IMPORTANT
The air conditioning system must be run
for a minimum of five minutes each week
regardless of the season to lubricate the
system and prevent damage to the seals.
Ensure a qualified technician is employed
for any repairs required.
COMMISSIONING
