Midea MAP05R1AWWT User Manual page 11

(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 of the refrigerant and shall be calibrated to the refrigerant employed and the
appropriate percentage of gas (25 % maximum) is confirmed. Leak detection
fluids are suitable for use with most refrigerants but the use of detergents con-
taining chlorine shall be avoided as the chlorine may react with the refrigerant
and corrode the copper pipe-work.
If a leak is suspected, all naked flames shall be removed/extinguished. If a leakage
of refrigerant is found which requires brazing, all of the refrigerant shall be recov-
ered from the system, or isolated (by means of shut of valves) in a part of the
system remote from the leak. Removal of refrigerant shall be according to Re-
moval and evacuation.
11.Removal and evacuation
When breaking into the refrigerant circuit to make repairs – or for any other pur-
pose–conventional procedures shall be used.
However, for flammable refrigerants it is important that best practice be followed,
since flammability is a consideration. The following procedure shall be adhered to:
a) safely remove refrigerant following local and national regulations;
b) purge the circuit with inert gas;
c) evacuate (optional for A2L);
d) purge with inert gas (optional for A2L);
e) open the circuit by cutting or brazing.
The refrigerant charge shall be recovered into the correct recovery cylinders if
venting is not allowed by local and national codes. For appliances containing
flammable refrigerants, the system shall be purged with repeated several times.
Compressed air or oxygen shall not be used for purging refrigerant systems. For
appliances containing flammable refrigerants, refrigerants purging shall be
achieved by breaking the vacuum in the system with oxygen-free nitrogen and
continuing to fill until the working pressure is achieved, then venting to atmo-
sphere, and finally pulling down to a vacuum (optional for A2L). This process shall
be repeated until no refrigerant is within the system (optional for A2L). When the
final oxygen-free nitrogen charge is used, the system shall be vented down to
atmospheric pressure to enable work to take place. Ensure that the outlet for the
vacuum pump is not close to any potential ignition sources and that ventilation is
available.
12.Charging procedures
In addition to conventional charging procedures, the following requirements shall
be followed. Ensure that contamination of di erent refrigerants does not occur
when using charging equipment. Hoses or lines shall be as short as possible to
minimise the amount of refrigerant contained in them. Cylinders shall be kept in
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