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A2L Work Procedures
immediately, but it is necessary to continue operation, an
adequate temporary solution shall be used. This shall be
reported to the owner of the equipment, so all parties are
advised.
Initial safety checks shall include:
•
Cabling is not subject to wear, corrosion, excessive
pressure, vibration, sharp edges, or any other adverse
environmental effects. Account for the effects of aging
or continual vibration from sources such as
compressors or fans.
•
Capacitors are discharged. This shall be done in a safe
manner to avoid possibility of sparking.
•
No live electrical components and wiring are exposed
while charging, recovering, or purging the system.
•
Verify continuity of earth bonding.
•
Replace electrical components with Trane replacement
parts, or those meeting the same ratings and qualified
for flame arrest protection, UL LZGH2 category.
Leak Detection
Never use an open flame to detect leaks. A halide torch
should not be used. Use only approved leak detection
methods per this instruction manual.
The following leak detection methods are deemed
acceptable for all refrigerant systems.
Electronic leak detectors may be used to detect refrigerant
leaks but, in the case of flammable refrigerants, the
sensitivity may not be adequate, or may need re-
calibration. (Detection equipment shall be calibrated in a
refrigerant-free area.) Ensure that the detector is not a
potential source of ignition and is suitable for the refrigerant
used. Leak detection equipment shall be set at a
percentage of the LFL gas (25% maximum) is confirmed.
Leak detection fluids are also suitable for use with most
refrigerants but the use of detergents containing chlorine
shall be avoided as the chlorine may react with the
refrigerant and corrode the copper pipe-work.
Examples of leak detection fluids are:
•
Bubble method
•
Fluorescent method agents
If a leak is suspected, all naked flames shall be removed/
extinguished.
If a refrigerant leak is found which requires brazing, all
refrigerant shall be recovered from the system, or isolated
(by means of shut off valves) in a part of the system remote
from the leak.
Refrigerant Removal and
Evacuation
When breaking into the refrigerant circuit to make repairs –
or for any other purpose – conventional procedures shall
be used. However, for flammable refrigerants it is important
16
that best practice be followed, since flammability is a
consideration.
The following procedure shall be adhered to:
1. Safely remove refrigerant following local and national
regulations.
2. Evacuate.
3. Purge the circuit with inert gas.
4. Evacuate (optional for A2L).
5. Continuously flush or purge with inert gas when using
flame to open circuit.
6. Open the circuit.
Prior to refrigerant removal, open all appropriate valves,
including solenoid and electronic expansion valves (EXVs).
Use control settings, where available. When not available,
manually open all electronically controlled valves using
acceptable service procedures.
The recovery equipment shall be in good working order
with instructions available. Equipment shall be suitable for
the recovery of the flammable refrigerant. For specific
handling concerns, contact the manufacturer. Ensure all
hose connections are checked for tightness to avoid
refrigerant leaks.
The refrigerant shall be recovered into the correct recovery
cylinders if venting is not allowed by local and national
codes. Do not mix refrigerants in recovery unit and
especially not in cylinders.
Refrigerant recovery unit should be purged with an inert
gas after each use or before using with a different
refrigerant Class – for example, A2L to A1.
If compressors or compressor oils are to be removed,
ensure that they have been evacuated to an acceptable
level to make certain that flammable refrigerant does not
remain within the lubricant. The compressor body shall not
be heated by an open flame or other ignition sources to
accelerate this process. When oil is drained from a system,
it shall be carried out safely.
The system shall be purged with oxygen-free nitrogen to
render the appliance safe for flammable refrigerants. This
process might need to be repeated several times.
Compressed air or oxygen shall not be used for purging
refrigerant systems.
The system shall be vented down to atmospheric pressure
to enable work to take place.
The outlet for the vacuum pump shall not be close to any
potential ignition sources, and ventilation shall be available.
Refrigerant Charging
In addition to conventional charging procedures, the
following requirements shall be followed.
•
Ensure that contamination of different refrigerants does
not occur when using charging equipment.
•
Hoses or lines shall be as short as possible to minimize
the amount of refrigerant contained in them.
ARTC-SVX008A-EN
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