Haier AW042MUGHA Installationsanleitung Seite 17

Safety
The following methods for detecting leaks are considered suitable for all types of
refrigerant systems:
1. Leak detection should be conducted using equipment with a sensitivity of 5 grams
per year of refrigerant or better under a pressure of at least 0.25 times the
maximum allowable pressure (>0.98MPa, max 3.90MPa). A universal sniffer, for
instance.
2. Electronic leak detectors can be used for flammable refrigerants, but they may
require recalibration for adequate sensitivity.(The calibration of detector should be
done in an area free of refrigerant.)
3. Ensure the detector does not pose a risk of ignition and is compatible with
the refrigerant being used.
4. The detector should be calibrated to the specific refrigerant used and set to
a percentage of the refrigerant's Lower Flammable Limit (LFL), ensuring it doesn't
exceed 25%.
5. Leak-detecting fluids, such as bubble or fluorescent method agents, can be used
with most refrigerants. However, detergents with chlorine should be avoided as
they can react with the refrigerant and corrode copper piping.
6. If a leak is suspected, eliminate any potential ignition sources.
7. If a leak requires brazing to repair, all refrigerant must be recovered from the
system first. Must follow the related precautions to remove the refrigerant.
Conventional procedures should be followed when needing to access the
refrigerant circuit for repairs or other purposes. Flammability factor must be taken
into account, and follow below procedures:
remove refrigerant ->purge the circuit with inert gas ->evacuate ->purge with inert gas
->open the circuit by cutting
Brazing is prohibited.
Recover the refrigerant charge into the appropriate recovery cylinders.
Purge the system with Oxygen Free Nitrogen (OFN) to ensure safety.
Repeat this process for several times as necessary.
Compressed air or oxygen is prohibited for this task.
The purging process involves filling the system with OFN until working pressure
is achieved, venting to atmosphere, pulling down to a vacuum, and repeating
until no refrigerant remains in the system. (Until the concentration of purge gas is
0.25 LFL or less by the leak detector). ø0.25LFL = 0.525Vol%
After the final OFN charge, vent the system down to atmospheric pressure
before starting any work.
This process is crucial if brazing on the pipework is needed.
Removal and Evacuation
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