22
Fig. 18 – Vacuum Pump Application
6.4 Charging the system
Once all electrical connections are correctly made, the unit is ready to be commissioned.
Refrigerant may only be added
after performing a leak test and system evacuation.
Start the system in cool mode and allow it to stabilise before checking liquid line sub-cooling and compressor suction
superheat. Refer to Start Up and Commissioning procedures (Section 7).
•
The system is pre-charged with R410a refrigerant for 10m actual pipe length
•
For lengths greater than 10m, additional charge is required. This is done by starting the unit and using it to draw
refrigerant (liquid only) through the compressor suction pipe Schrader valve, located in the compressor
compartment. Refer to Section 6.2.
•
Refrigerant containers should be opened slowly to avoid injury.
•
Always use protective gloves and protect your eyes when charging refrigerant.
Additional Refrigerant Charge
For pipe lengths greater than 10m an additional 30g/m of refrigerant is required. The maximum total pipe length for
all units is 65m.
The correct measurement and assessment of superheat and sub-cooling values should be the only measures used
to confirm correct system charge
.
•
Superheat should be between 4 and 9K
•
Sub-cooling should be between 2 and 8K
•
Discharge gas temperature should not exceed 130°C in any circumstances
•
Do not overcharge.
