EarthLinked SCWD-024-1C, Quick Start Instructions

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SCWD-QS (12/16) Page 58
Triple Evacuation
Triple evacuation is implemented to evacuate a system to a deep vacuum. It is accomplished by
evacuating a system to a vacuum of 1500 microns, and then bleeding a small amount of dry nitrogen
into the system. The nitrogen is then blown out to the atmosphere. The system is then evacuated
until the vacuum is again reduced to 1500 microns. This procedure is repeated three times, with the
last vacuum level reaching a deep vacuum of 400 microns, which is held for 10 to 15 minutes. The
following is a detailed description of the triple evacuation.
1. Attach an electronic micron gauge to the system. The best place is as far from the vacuum
port as possible, which would be the access port on a service valve on the EarthLinked
®
compressor unit.
2. Let the vacuum pump run until the digital vacuum gauge reaches 1500 microns. After
reaching 1500 microns, isolate the digital vacuum gauge.
3. Purge hoses with nitrogen. Then, allow a small amount of dry nitrogen to enter the system
until the LP gauge shows about 5 psig. This small amount of dry nitrogen will fill the system
and mix with the other vapors.
4. Release system pressure to 0 psig and close the valve. Then open the isolation valve on the
digital vacuum gauge.
5. Open the vacuum pump valve and start the vapor removal process from the system again.
Let the vacuum pump run until the vacuum is again reduced to 1500 microns.
Repeat Step 3.
6. After nitrogen has been added to the system a second time , open the vacuum pump valve
and again remove the vapor. Operate the vacuum pump until the vacuum on the electronic
micron gauge reads
400 microns.
7. Once the micron gauge reads 400 microns for 10 to 15 minutes , isolate the micron gauge.
The system must not exceed 500 microns in 15 minutes. If it does, repeat step 6 .
8. Then charge the system in accordance with the initial refrigerant charging procedure.