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Start Up and Operation
Before commissioning, ensure that all valves on the condensing unit are fully opened.
Evacuation
The evacuation procedure is based upon achieving an actual system vacuum standard and is not time dependent. Before the
installation is put into commission, it has to be evacuated with a vacuum pump. Proper evacuation reduces residual moisture
to 50ppm. The installation of adequately sized access valves at the furthest point from the compressor in the suction and liquid lines is
advisable. To achieve undisturbed operation, the compressor valves are closed and the system is evacuated down to 0.3 mbar / 0.225
Torr. Pressure must be measured using a vacuum pressure (Torr) gauge on the access valves and not on the vacuum pump; this serves to
avoid incorrect measurements resulting from the pressure gradient along the connecting lines to the pump.
Charging Procedure
Refrigerant charging procedure
The scroll compressor design requires system charging as quickly as possible with liquid refrigerant into the liquid line. This will
avoid running the compressor under conditions where there is insufficient suction gas. Sufficient suction gas is available to cool not only
the motor but also the scrolls. Temperature builds up very quickly in the scrolls if this is not done. Do not charge vapor (gas) refrigerant
into the ZX Scroll unit. The suction service valve must not be fully closed at any time while the compressor is running. To do so would
cause damage to the compressor in the same manner as explained above. This valve is provided for ease of connection and for the
fitting of service gauges without removing the unit panel. It is recommended to charge the ZX unit with refrigerant via its service valves.
It is recommended to break the vacuum in the system with a partial charge of the refrigerant, before starting the system. For charge
adjustment, it is recommended to check the liquid sight glass just before the expansion valve.
Oil charging procedure
Emerson ZX condensing units are supplied only with a compressor oil charge. After commissioning, the oil level should be
checked and topped up if necessary. The oil level should be approximately halfway up the sight glass (ZXL/ZXD units). Oil can be charged
through the Schraeder valve on suction valve.
Scroll compressor rotation direction
Scroll compressors, like several other types of compressors, will only compress in one rotational direction. The direction of
rotation is not an issue with single-phase compressors since they will always start and run in the proper direction. Three- phase
compressors will rotate in either direction depending upon the phasing of the power. Since there is a 50-50 chance of connecting power
in such a way that causes rotation in the reverse direction, it is important to include notices and instructions in appropriate locations on
the equipment to ensure proper rotation direction when the system is installed and operated.
Maximum compressor cycle
Maximum permitted starts per hour is 10.
Check before starting & during operation
Both valves should be fully opened on the liquid line, in order to prevent trapping liquid.
• Check that all valves are fully opened.
• After starting and operation conditions are stabilized, it is recommended to check the oil level in compressor(s) and see if
there is a need to add oil to ensure a sufficient oil level (halfway up the sight glass).
Controller Initialization Message
When the unit is initially powered on, the controller will display.
Step
Action
1
Power on controller
2
3
4
18
Phenomenon and Description
All LEDs will light up for 3 seconds.
Firmware version will be displayed for 3 seconds.
Parameter setting file (bin file number) identifier will be displayed for 3 seconds.
Normal display (actual suction temperature will be displayed on ZXD unit, condensing
temperature will be displayed on ZX/ZXL/ZXB unit)
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