7
AFTER SALES SUPPORT
1300 886 649
AUS
MODEL: PA19W PRODUCT CODE: 703227 11/2020
8. Leak detection methods
The following leak detection methods are deemed acceptable for all refrigerant
systems.
8.1 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 (lower flammable limit, 0.038 kg/m
3
) of the refrigerant
and shall be calibrated to the refrigerant employed, and the appropriate
percentage of gas (25% maximum) is confirmed.
8.2 Leak detection fluids are 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.
8.3 If a leak is suspected, all naked flames shall be removed/extinguished.
8.4 If a leakage of refrigerant is found which requires brazing, all of the 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. Oxygen-free nitrogen (OFN)
shall then be purged through the system both before and during the brazing
process.
9. Removal and evacuation
9.1 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 that best practice is followed since flammability is a
consideration. The following procedure shall be adhered to:
– remove refrigerant
– purge the circuit with inert gas
– evacuate
– purge again with inert gas
– open the circuit by cutting or brazing.
9.2 The refrigerant charge shall be recovered into the correct recovery cylinders.
The system shall be “flushed” with OFN to render the unit safe. This process
may need to be repeated several times. Compressed air or oxygen shall not be
used for purging refrigerant systems.
9.3 Flushing shall be achieved by breaking the vacuum in the system with OFN
and continuing to fill until the working pressure is achieved, then venting to
atmosphere, and finally pulling down to a vacuum. This process shall be
repeated until no refrigerant is within the system. When the final OFN charge is
used, the system shall be vented down to atmospheric pressure to enable work
to take place. This operation is absolutely vital if brazing operations on the pipe
work are to take place.
Service Instructions (Cont.)
