Data Aire gForce Ultra Installation, Operation And Maintenance Manual Download

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Care must be taken to prevent charging the system with too much refrigerant

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See directions for system charging in sections 5.3 Air Cooled System Charging or 5.4 Flood-

ed System Charging

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The return air temperature to the unit being charged must be stable and must be maintained

greater than 65°F (18°C)

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If this is not possible due to lack of heat load, then load banks must be used to offset the

cooling load during startup

5.2 Triple Evacuation
Data Aire highly recommends a triple evacuation to be carried out on all Data Aire units, to insure the

highest quality vacuum. Moisture prevents the proper operation of both the compressor and the re-

frigeration system. Non-condensables and moisture reduces service life and increases condensation

pressure, which causes abnormally high discharge temperatures that are capable of degrading the

lubricating properties of the oil. The risk of acid formation is also increased by non-condensables and

moisture, and this condition can also lead to copper plating. All of these phenomena may cause both

mechanical and electrical compressor failure. The typical method for avoiding such problems is to

evacuate the system.

It is of the utmost importance that proper system evacuation and leak detection procedures be em

ployed. Good evacuation processes include frequent vacuum pump oil changes and large diameter,

short hose connections to both high and low sides of the system preferably using copper tubing or

braided hose. All valves in the system, both liquid line solenoid valve and rotolock service valves (if the

compressor is equipped with them), need to remain open during the vacuum process and the system

must be purged of nitrogen. We recommend using a solenoid magnet tool to hold the liquid line sole-

noid valve open. A deep vacuum gauge capable of registering pressure in microns should be attached

to the system for pressure readings. A shut-off valve between the gauge connection and vacuum

pump should be provided to allow the system pressure to be checked after evacuation. Do not turn off

vacuum pump when connected to an evacuated system before closing shut-off valve.
Triple evacuate the refrigerant lines, condenser coil and evaporator coil to 500 microns or lower (a mi

cron gauge and 2-stage vacuum pump are required).

Perform these procedures without contaminating the system with non-condensables

Step 1: Evacuate system down to 4000 microns from both service valves. Then close the manifold

gauges, shut off the vacuum pump and introduce dry nitrogen up to 5psi to the system without contami

nating it. Then release the nitrogen and restart the vacuum pump.

Step 2: Evacuate system down to 1500 microns from both service valves. Then close the manifold

gauges, shut off the vacuum pump and introduce dry nitrogen up to 5psi to the system without contami

nating it. Then release the nitrogen and restart the vacuum pump.

Step 3: Evacuate system down to 500 microns or below from both service valves.
Turn off the vacuum pump and conduct a rise test waiting at least 30 minutes to make sure the micron

gauge reading does not go back above 500 microns. If it does, restart the vacuum pump and evacuate

until the system reaches 500 microns. If the system still does not hold the pressure below 750 microns

the system needs to be rechecked for leaks.