Structural Concepts Harmony HMBC2 User Manual page 17

Preventive Maintenance
Maintenance and Service Notes
WARNING! TURN OFF CASE BEFORE PERFORMING PREVENTATIVE MAINTENANCE
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 that the 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 change 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 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, refrigerant 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 (optional for A2L). This process shall be repeated until no refrigerant is within the
system (optional for A2L). When the final oxygen-free nitrogen change 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.
Charging procedures
• In addition to conventional charging procedures, the following requirements shall be followed.
a. 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.
b. Cylinders shall be kept in an appropriate position according to the instructions.
c. Ensure that the REFRIGERATING SYSTEM is earthed prior to charging the system with refrigerant.
d. Label the system when charging is complete (if not already).
e. Extreme care shall be taken not to overfill the REFRIGERATING SYSTEM.
• Prior to recharging the system. It shall be pressure-tested with the appropriate purging gas. The system shall be lead-
tested on completion of charging but prior to commissioning. A follow up leak test shall be carried out prior to leaving the
site.
Harmony® User Manual 17