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Refrigerant Charging
Reminder
∙ The scroll compressor design requires system charging with liquid refrigerant into the liquid line.
∙ Do not vapor charge the ZX Scroll unit.
After ensuring all valves are opened and system is vacuumed properly, only then start the refrigerant charging process
Step-by-step:
1. Ensure that there is no power supply to the ZX unit. The Liquid Line solenoid needs to be kept open for the charging process and this
may require a temporary power feed to it.
2. Connect the refrigerant cylinder to main service hose and purge line at the manifold end.
3. Ensure correct orientation of the refrigerant cylinder. Follow cylinder labeling/instructions so that liquid refrigerant can be charged
into the system. This will be charged through the high-pressure side of the manifold and ZX unit liquid service valve.
4. The refrigerant cylinder should be weighed at this point to be able to record the final refrigerant charge. Note that the standard
receiver capacity is 4.4 kg of refrigerant for single-fan units and 6.3 kg of refrigerant for dual-fan units at 80% capacity and 32°C
ambient temperature (R404A).
5. Now open the liquid service valve (off the back seat). With a good vacuum in the system, the refrigerant cylinder correct orientation
and at ambient, you should not need to run the compressor at all.
6. The compressor can then be started, and the unit continued to be charged (with liquid refrigerant through the liquid service valve).
The quantity of charge should always be measured. See note.
7. Turn off the unit and open the receiver outlet valve (which was almost fully closed earlier).
8. The system needs to be operated down to its design evaporating temperature before you can be sure the charge is correct. It is at this
point that the normal refrigeration operational checks can be carried out - such as checking the liquid line sight glass for violent
bubbles and the operating pressures.
In the event that the system is still short of refrigerant, repeat from step #5 onwards.
Refrigerant charging is regarded full/complete when the operating temperature of the system has been stable for some time and the
liquid line sight glass is clear.
Electrical (Power) Connections
ZX Condensing units’ uses 3-Phase Scroll compressors and can rotate in the wrong direction when starting. If this
happens reverse any two phases (L1 & L3) and start again. Built-In Electrical Contactors – Requires 3-Phase Power Supply Line ONLY (as
shown) NO ADDITIONAL CONNECTIONS at the ON-BOARD CONTACTORS
Maximum Compressor Cycle
Maximum permitted starts per hour is 10.
KEEP IN MIND
ZX CDU Field Wiring Connections: L1, L2, L3 and Neutral Line (N)
