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8. Carefully release the nitrogen charge. Watching the gauge until it reads 5 PSIG.
5.1.4. Third Stage Evacuation
1. Move the vacuum hoses back to the vacuum pump and restart the pump.
2. Open the Schrader core shutoff valve and evacuate the refrigerant system from both sides
of the system to 1200 micron or less.
3. Close the Schrader core shutoff valve and turn OFF the vacuum pump.
4. Conduct a rise test by waiting at least 10 minutes to make sure the micron gauge reading
does not go above 1250 microns.
5. Disconnect the vacuum pump hoses from the vacuum and attached them to your manifold
gauges.
6. Connect a vacuum hose from the nitrogen bottle regulator to the manifold gauges vacuum
port and carefully break the vacuum with clean dry nitrogen. Slowly raise the pressure to
approximately 5 PSIG without contaminating the system.
7. Isolate and hold the nitrogen charge for at least one (10) minutes.
8. Verify no nitrogen leaks.
9. Carefully release the nitrogen charge. Watching the gauge until it reads 5 PSIG.
5.1.5. Final Evacuation Stage
1. Move the vacuum hoses back to the vacuum pump and restart the pump.
2. Open the Schrader core shutoff valve and evacuate the refrigerant system from both sides
of the system to 500 micron or less.
3. Close the Schrader core shutoff valve and turn OFF the vacuum pump.
4. Conduct a rise test by waiting at least 30 minutes to make sure the micron gauge reading
does not go above 500 microns.
5. Conduct a second rise test by waiting at least 30 minutes. If system rises above 750
microns, restart the vacuum pump and evacuate until the system reaches 500 microns.
6. If the vacuum increases more than 750 microns but holds at a higher micron level (i.e.,
does not reach atmosphere), this indicates that there is still moisture in the system, but
not a leak. The unit must be put back on the pump for more dehydration.
7. If the vacuum reaches atmosphere, then the unit has a leak. The leak must be found and
repaired before the unit is put back on the pump for dehydration.
8. After the system has been satisfactorily evacuated the evacuation equipment can be
removed and the system can be charged with refrigerant.
9. Make sure all service and field installed ball valve are open and remain open for changing.
10. Ensure all valve cores and caps are re-installed on the Schrader port and on the Rotolock
service valves.