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8 A/C service preparation
8.1
Preliminary preparation
Warning - risk of burns from hot
engine components
Contact with hot engine
components will cause severe
burns.
Allow the engine to cool down.
Wear protective goggles.
Wear protective gloves.
Warning - risk of frostbite from
escaping refrigerant
Refrigerant causes frostbite on the
skin.
Check the service hoses for damage.
Firmly connect the service quick-
release couplings to the service
hoses.
Wear protective goggles.
Wear protective gloves.
Perform the following preparatory work prior to
vehicle A/C service: Service hoses must be
constructed of the proper materials and have the
lengths as supplied by the unit. Hoses must have
shut-off devices (quick-release couplers) at the
connection point to the A/C to minimize the
introduction of air into the AC442 and to minimize the
amount of refrigerant released while disconnecting
the hoses.
Inspect hoses for signs of damage prior to
performing A/C service. Use of damaged hoses will
result in the loss of refrigerant and the possibility of
refrigerant contamination.
Follow the vehicle manufacturer's recommendations
for A/C service on vehicles with a low-pressure
connection only.
A/C service operations (especially recovery) should be
performed after the vehicle has been run for a period
of time to allow engine heat to raise system pressure.
This allows for the maximum refrigerant recovery
amount to occur. If system is excessively hot, the
recharge phase could be adversely effected
The AC442 is only to be operated with R134a
refrigerant. Check with refrigerant is used for the
vehicle before performing A/C service.
Never attempt to close the valves of the internal
refrigerant bottle while the AC442 is in operation.
Only new lubricant as specified by the system
manufacturer shall be installed in vehicle A/C system.
Lubricant removed from the system and or equipment
shall be disposed of in accordance with the applicable
federal, state and local procedure and regulations.
1901016-85
8.2 Non-condensable gas discharge
If the AC442 detects non-condensable gases in the
internal cylinder, the unit will prompt technician to
allow unit to run an air purge. This prompt will occur
every time unit is powered on (if unit has been
powered off for at least 1 hour.)
The process will perform automatically upon the
start of a charge procedure if non-condensables are
detected.
Air purge is a necessary process to ensure ideal working
parameters for the AC442. Presence of non-condensable
gases will increase tank pressure and reduce efficiency of
recharge cycles.
8.3 Charge Modes
The AC442 has 2 different refrigerant charge
methods. If charge does not complete using Quick
mode, the zero tolerance method automatically
commences
8.3.1
Quick Modes
In Quick mode, the AC442 injects refrigerant through HP port.
The refrigerant remains in the hoses at the end of the cycle
and is then recovered during a hose clearing process.
8.3.2
Zero tolerance mode
While the Zero tolerance mode is slightly longer in time, it
provides a more accurate recharge and guarantees a
successful charge.
In Zero tolerance mode, the AC442 will by default charge
through the HP (red) hose, then refrigerant that remains in
the hoses is pulled into the vehicle's A/C system through the
.
LP (blue) hose.
In the instance where only a LP coupling is available for
A/C service, the AC442 will charge the system with 50%
of the total charge amount with the vehicle A/C
compressor off. The unit then waits 10 minutes to allow
the liquid refrigerant to evaporate to prevent damage to
the compressor. The vehicle must be started and the A/C
system turned on. The AC442 will continue to charge the
refrigerant whenever the LP hose pressure is less than 3
bar.
A/C System service | AC442 | 18 en
The service parameters (recharge quantity) can be
found in the owner's manual or the vehicle repair
manual.
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