© MAHLE
A/C service preparation | ACX2120H | 17 en
8.
A/C service preparation
8.1
Preliminary preparation
Warning - risk of burns from hot engine
components
Warning - risk of frostbite from escaping
refrigerant
Refrigerant causes frostbite on the skin.
Contact with hot engine components will
cause severe burns.
Allow the engine to cool down.
Wear protective goggles.
Wear protective gloves.
Check the service hoses for damage.
Firmly connect the service quick-release cou -
plings to the service hoses.
Wear protective goggles.
Wear protective gloves.
Perform the following preparatory work prior to vehicle A/C service:
m
Service hoses must be contructed of the proper materials and
have the lengths as supplied with the unit. Hoses must have
shut devices (quick-release couplers) at the connection point
to the A/C to minimize the introduction of air into the ACX2120H
and to minimize the amount of refrigerant released while discon -
necting the hoses.
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Inspect hoses for signs of damage prior to performing A/C
service. Use of damaged hoses will result in the loss of refriger -
ant and the possibility of refrigerant contamination.
t
Follow the vehicle manufacturer's recommendations for A/C
service on vehicles with a low-pressure connection only.
1.
Set the A
ration-proof surface.
2.
Actuate the caster brake to stop the unit from rolling.
3.
Connect the power supply cable to the power supply.
4.
Switch on the main switch.
t
Follow the manufacturer's instructions for the corresponding
vehicle before performing A/C service.
t
A/C service operations (especially recovery) should be per -
formed 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
ted.
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The ACX2120H is only to be operated with R134a refrigerant.
Check which refrigerant is used for the vehicle before perform -
ing A/C service.
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The ACX2120H cannot be used for air conditioning systems
repaired using a chemical sealant. Non compliance will void the
warranty.
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Never attempt to close the valves of the internal refrigerant bottle
while the ACX2120H is in operation.
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Only new lubricant, as
by the system manufacturer,
shall be installed in the MAC system. Lubricant removed from the
system and/or equipment shall be disposed of in accordance with
the applicable federal, state, and local procedures and regulations.
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The service parameters (recharge quantity) can be found in the
owner's manual or the vehicle repair manual.
8.2
Non-condensible gas discharge
t
If the ACX2120H detects non-condensible 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 power
r at least 1 hour).
t
The process will perform automatically upon the start of a charge
procedure if non-condensibles are detected.
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Air purge is a necessary process to ensure ideal working parame -
ters for the ACX2120H. Presense of non-condensible gases will
increase tank pressure and reduce
ncy of recharge cycles.
8.3
Charge modes
t
The ACX2120H has 2
rent refrigerant charge methods. If
charge does not complete using Quick mode, the Zero tolerance
method automatically commences.
8.3.1
Quick mode
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In Quick mode, the ACX2120H injects refrigerant through the
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
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While the Zero tolerance mode is slightly longer in time, it provides
a more accurate recharge and guarantees a successful charge.
t
In Zero tolerance mode, the ACX2120H will by default charge
throught 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.
t
In the instance where only a LP coupling is available for A/C serv-
ice, the ACX2120H will charge the system with 50% of the total
charge amount with the vehicle A/C compresor
The unit then
waits 10 minutes to allow the liquid refrigerant to evaporate to pre -
vent damage to the compressor. The vehicle must be started and
the A/C system turned on. The ACX2120H will continue to charge
refrigerant whenever the LP hose pressure is less than 3 bar.
