Chapter 6 System Maintenance 41
New Liebert_DM Series Air Conditioner User Manual
6. Install replacement compressor and make all connections. Do pressurization and leakage tests to the system at
approximately 150psig (1034kPa).
7. Evacuate the system twice to 1500 microns and the third time to 500 microns. Break the vacuum each time with
clean and dry refrigerant to 2psig (13.8kPa).
8. Charge the system with refrigerant based on the requirements of the evaporator, condenser and refrigeration lines.
9. Apply power to and operate the AC unit. Check for proper operation. Refer to the circulation suction pressure and
discharge pressure ranges in normal operation, and supplement some refrigerant if necessary.
6.3 Outdoor Unit Maintenance
6.3.1 Refrigeration System
The components of the refrigerant system should be inspected monthly for finding abnormal operation phenomenon
in time. Refrigerant pipes must be properly fixed and not allowed to vibrate against wall, floor or the unit frame.
Inspect all refrigerant pipes every six months for signs of wear.
6.3.2 Air-Cooled Condenser
When the airflow through the outdoor unit is restricted, use compressed air or fin cleaner (alkalescence) to clean the
condenser off the dust and debris that inhibit airflow. The compressed air should be blown at the reversed airflow
direction. In winter, do not let snow to accumulate around the side or underneath the condenser. Check for bent or
damaged fins and simply repair them if necessary. Check all refrigerant pipes and capillaries for vibration and support
them if necessary. Carefully inspect all refrigerant pipes for signs of oil leakage, determining the leakage position.
6.3.3 Low-Temperature Unit Of Lee-Temp Outdoor Unit
Periodically check the liquid level of the refrigerant in fluid reservoir to ensure that no refrigerant leakage happens.
For detailed operation, refer to 4.2.5 Checking Refrigerant Charge Capacity Of Lee-Temp Outdoor Unit.
Periodically check whether the heating belt of the fluid reservoir works normally. See following for details:
When the system is powered on and standby, and the fluid reservoir pressure is lower than 0.85Mpa, the heating belt
preheats the fluid reservoir. If the heating does not happen, check whether the fuse of the heating belt is blown or if
the pressure switch works normally. After confirming the fault part(s), replace it or them.
The heating belt fuse specifications are listed in Table 6-2.
Table 6-2 Fuse specifications
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