45MBDAQ: Installation Instructions
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
7
NOTE: Examples of leak detection fluids are
- bubble method,
- fluorescent method agents.
If a leak is suspected, all open flames shall be
removed/extinguished. 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. See the
following instructions of removal of refrigerant.
7. 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 that best practice be
followed, since flammability is a consideration. The following
procedure shall be adhered to:
- safely recover refrigerant following local and national regulations;
evacuate;
- purge the circuit with NITROGEN;
- evacuate (requirement);
- continuously flush or purge with NITROGEN when using flame to
open circuit; and
- open the circuit
The refrigerant charge shall be recovered into the correct recovery
cylinders. Charging must be performed by the liquid charging
method. For appliances containing flammable refrigerants, 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.
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 atmosphere, and finally pulling
down to a vacuum (requirement). This process shall be repeated
until no refrigerant is within the system (requirement). When the
final oxygen-free nitrogen charge is used, 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.
Recovery: When removing refrigerant from a system, either for
servicing or decommissioning, it is recommended good practice that
all refrigerants are removed safely.
When transferring refrigerant into cylinders, ensure that only
appropriate refrigerant recovery cylinders are employed. Ensure that
the correct number of cylinders for holding the total system charge is
available. All cylinders to be used are designated.
8. Charging Procedures
In addition to conventional charging procedures, the following
requirements shall be followed:
Works shall be undertaken with appropriate tools only (in case of
uncertainty, consult the manufacturer of the tools for use with
flammable refrigerants)
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.
Charging must be performed by the liquid charging method.
Ensure that the refrigeration system is grounded prior to charging the
system with refrigerant.
Label the system when charging is complete (if not already).
Extreme care shall be taken not to overfill the refrigeration system.
Prior to recharging the system it shall be pressure tested with oxygen
free nitrogen (OFN). The system shall be leak tested on completion
of charging but prior to commissioning. A follow up leak test shall
be carried out prior to leaving the site.
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