Evacuate And Dehydrate - Partial System; Refrigerant Charge - Carrier PrimeLINE 69NT40-561-200 Operation And Service Manual

4. Test the evacuation setup for leaks by backseating the unit service valves and drawing a deep vacuum with
the vacuum pump and gauge valves open. Shut off the pump and check to see if the vacuum holds. Repair
leaks if necessary.
5. Midseat the refrigerant system service valves.
6. Open the vacuum pump and electronic vacuum gauge valves, if they are not already open. Start the vacuum
pump. Evacuate the unit until the electronic vacuum gauge indicates 2000 microns. Close the electronic
vacuum gauge and vacuum pump valves. Shut off the vacuum pump. Wait a few minutes to be sure the vac-
uum holds.
7. Break the vacuum with either clean refrigerant (R-134a or R-513A as specified for the unit model number) or
dry nitrogen. Raise system pressure to roughly 0.14 bar (2 psig), monitoring it with the compound gauge.
8. If refrigerant was used, remove using a refrigerant recovery system. If nitrogen was used, relieve the pressure.
9. Repeat steps 6 and 7 one time.
10. Remove the copper tubing and change the filter drier. Evacuate unit to 500 microns. Close the electronic
vacuum gauge and vacuum pump valves. Shut off the vacuum pump. Wait five minutes to see if vacuum
holds. This procedure checks for residual moisture and/or leaks.
11. With a vacuum still in the unit, the refrigerant charge may be drawn into the system from a refrigerant con-
tainer on weight scales.
7.6.4

Evacuate and Dehydrate - Partial System

1. If refrigerant charge has been removed from the low side only, evacuate the low side by connecting the
evacuation set-up at the compressor suction valve and the liquid service valve but leave the service valves
frontseated until evacuation is completed.
2. Once evacuation has been completed and the pump has been isolated, fully backseat the service valves to
isolate the service connections and then continue with checking and, if required, adding refrigerant in accor-
dance with normal procedures.
7.7

REFRIGERANT CHARGE

EXPLOSION HAZARD Failure to follow this WARNING can result in death, serious personal
injury and / or property damage. Never use air or gases containing oxygen (O
or operating the product. Charge only with refrigerants R-134a or R-513A as specified for the
unit model number: Refrigerant must conform to AHRI Standard 700 specification.
7.7.1 Checking the Refrigerant Charge
Use a refrigerant recovery system whenever removing refrigerant. When working with refrigerants you
must comply with all local government environmental laws. In the U.S.A., refer to EPA Section 608.
1. Connect the gauge manifold to the compressor discharge and suction service valves. For units operating on
a water-cooled condenser, change over to air-cooled operation.
2. Bring the container temperature to approximately 0°C (32°F) or below. Then set the controller setpoint to -
25°C (-13°F).
3. Partially block the condenser coil inlet air. If covering the lower portion of the coil is not sufficient, remove the
left hand infill panel and cover the left side of the coil. Increase the area blocked until the compressor dis-
charge pressure is raised to approximately 12.8 bar (185 psig).
4. On units equipped with a receiver, the level should be between the glasses. On units equipped with a water-
cooled condenser, the level should be at the center of the glass. If the refrigerant level is not correct, refer to
Section 7.7.2 and
T-362
!
Section 7.7.3 to add or remove refrigerant as required.
WARNING
NOTE
7–6
) for leak testing
2