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3.
Start vacuum pump and draw system to 1,500 microns or less.
4.
Purge system with nitrogen to atmospheric pressure (0 gauge pressure). Ensure all portions
of systems are at this pressure. Seal system and wait 10 minutes.
5.
Start vacuum pump and draw system to 500 microns. Seal system. System may rise to
higher level, 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 of critical importance 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.
Desert Aire - LC/LV Manual
Summary of Contents for ExpertAire LC Series
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