Desert Aire Aura QS, Installation And Operation Manual

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Desert Aire - QS/QV Manual
but should not rise above 1000 microns in 10 minutes timeframe. If unsuccessful, continue
evacuation or check for leaks.
It is anticipated that the system was clean and tight from the original process and refrigerant only is mixed
with oil. Alternative process should not be considered if there is chance of free water entering the system or
the system was open for any significant time.
Charging
• Charge should be weighed into the system using a scale. In cases where the full charge was
recovered, weigh in the charge with the recovered refrigerant and add the appropriate amount to
meet the rating plate and field charge (if applicable). This should be placed in the high side of the
system at the receiver.
• In cases where the full charge cannot be added to the system high side, the charge can be added to
the low side of the system only when compressors are energized. If this is required, the
compressors should be energized and the charge should be slowly metered into the suction line
as far as possible upstream of the compressor. If the unit is equipped with an accumulator, the
charge needs to be added to the port upstream of this location. The bulkhead fittings on the side of
the unit should not be used for charge addition. Monitor superheat at the compressor suction inlet
using the bulkhead fitting and a temperature sensor on the suction line near the compressor.
Superheat should not drop below 10 degrees during the process of adding charge.
Testing and Final Diagnosis
Check the oil level in the compressor after the system has been running for 24 hours. Oil may have been
contained in the liquid refrigerant when recovered from the system. Most of this oil will be returned if the
recovered refrigerant is used. If new refrigerant is added, additional oil should be added based on the
following ratio:
New Refrigerant Charge Added, lbs. x 0.352 = Oil charge, oz.
It is critically important to ensure that the system is operating as expected before unit is returned to normal
service. Test component replaced and function of the system. Many times a separate component in the
system may have set a condition that causes a failure of another. Thoroughly test systems to ensure repeat
failures do not occur.
Note:
Compressors supplied with an oil sight glass should be viewed and filled to 50% capacity.