Carrier PC211 Start-Up, Operation And Maintenance Instructions Manual page 129

WARNING
Never charge liquid refrigerant into the machine if the pressure in the machine is
less than 68 psig (469 kPa) for HCFC-22 and 35 psig (241 kPa) for HFC-134a.
Charge as a gas only, with the cooler and condenser pumps running, until this
pressure is reached, using PUMPDOWN LOCKOUT and TERMINATE LOCKOUT
mode on the PIC. Flashing of liquid refrigerant at low pressures can cause tube
freezeup and considerable damage.
c. Leak test machine as outlined in Steps 3 - 9.
2. If the pressure readings are abnormal for machine condition:
a. Prepare to leak test machines shipped with refrigerant (Step 2h).
b. Check for large leaks by connecting a nitrogen bottle and raising the pressure to 30 psig
(207 kPa). Soap test all joints. If the test pressure holds for 30 minutes, prepare the test
for small leaks (Steps 2g - h).
c. Plainly mark any leaks which are found.
d. Release the pressure in the system.
e. Repair all leaks.
f. Retest the joints that were repaired.
!
WARNING