49
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 charging.
10. Ensure all valve cores and caps are re-installed on the Schrader port and on the Rotolock
service valves.
WARNING: Before applying power to the unit, the fuses to the fixed
speed compressor(s) must be removed to prevent compressor starting
inadvertently/automatically. When ready to start the charging
procedures, remove power and replace the fuses.
General Pre-Charging Guidelines
• Check the unit nameplate for refrigerant type to be used.
• The unit must be piped and wired correctly for operation.
• Always use a scale to weigh in the calculated refrigerant charge listed in tables in
individual compressor charging sections before starting the unit, record system charge
when completed.
• Confirm all the valves in the system are fully open, except for the EEV or TXV.
• The initial refrigerant must be charged with 80% of the circuit volume. The charge must
be applied after the second check valve on the discharge line with the compressor OFF.
This will fill the high side of the system.
• If the EEV or TXV is in the close position, use a liquid charging adapter to break the
vacuum at the compressor suction and discharge Rotolock service valves with 90 PSIG
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