CAUTION: Always use the compressor pumpdown function in the Control Test mode to turn on the evaporator pump and lock out the compressor when transferring refrigerant. Liquid refrigerant may flash into a gas and cause possible freezeup when the chiller pressure is below 35 psig (241 kPa).
Adjusting the Refrigerant Charge
Refrigerant Leak Testing
Refrigerant Leak Rate
Test After Service, Repair, or Major Leak
TO PRESSURIZE WITH DRY NITROGEN: Another method of leak testing is to pressure with nitrogen only and use soap bubble solution or an ultrasonic leak detector to determine if leaks are present. This should only be done if all refrigerant has been evacuated from the vessel.
Repair the Refrigerant Leak, Retest, and Apply Standing Vacuum Test
Trim Refrigerant Charge
Source: Carrier (www.shareddocs.com)