Refrigeration Maintenance (Rev. 04/03)
66
11. If the vacuum level is acceptable, start the pump and
open valve V-1 to evacuate the pressure rise (5 min-
utes).
12. Close valve V-1 and stop the pump. Observe the micron
gauge to confirm that the system remains in a deep vac-
uum. Close valve V-4. The unit is ready to charge.
Unit Charging
NOTE: Refer to the diagram on the next page for the fol-
lowing discussion.
NOTE: Before charging, make sure that the refrigerant
lines from the gauge manifold to the refrigerant supply
bottle have been evacuated or purged.
1. Back seat the suction service valve. The discharge and
receiver outlet valves remain open to port.
2. Set the refrigerant supply bottle for liquid. Open the
gauge manifold hand valve, and charge liquid refriger-
ant until the system has the proper charge or until the
system will take no more liquid. The remainder of the
charge will be added as a vapor through the suction ser-
vice valve if more refrigerant is required.
3. After the liquid refrigerant is added, close the gauge
manifold hand valve. Close the valve on the refrigerant
supply bottle and set for vapor.
4. Back seat (close) the receiver outlet valve. Back seat
the discharge service valve. Open the suction service
valve.
5. Open the refrigerant supply valve for vapor. Open the
gauge manifold hand valve.
6. Start and operate the unit with the thermostat set for
cool. Add vapor through the suction service valve until
the correct charge is attained. Make sure that the liquid
level does not rise above the sight glass. Refer to the
unit serial plate for the correct amount of charge.
7. When the correct amount of charge has been added,
close the gauge manifold hand valve.
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