Check A Running Compressor; Refrigerant Handling; Commissioning - Data Aire gForce Ultra Installation, Operation And Maintenance Manual

5.7

Check a Running Compressor

• Check current draw and voltage.
• Check suction superheat to reduce risk of slugging.
• Observe the oil level at start and during operation to confirm that the oil level remains visible.
• Excess foaming in oil sight glass indicates refrigerant on the sump.
• Monitor the oil sight glass for 1 hour after system equilibrium to ensure proper oil return to
the compressor. This oil check has to be done over the speed range to guarantee:
- A good oil return at low speed with minimum gas velocity.
- A good oil management at high speed with maximum oil carry over.
• Check all tubes for abnormal vibration. Movements in excess of 1.5 mm require corrective
measures such as tube brackets.
• When needed, add refrigerant.
• Do not overcharge the system.
• Record type and amount of refrigerant charge as well as operating conditions as a reference
for future inspections.
5.8

Refrigerant Handling

The use of recovery/recycling units is required by U.S. Environmental Protection Agency (EPA) regula-
tions. Technicians who service and dispose of air conditioning and refrigeration equipment must re-
cover the refrigerant instead of venting it to the atmosphere.
Except for extremely small releases of refrigerant such as what occurs when disconnecting service
hoses, a technician who knowingly releases or vents refrigerant to the atmosphere is in violation of this
regulation. Refrigerant purchasers must be certified technicians and have a valid EPA certification card.
WARNING:
the latest edition of ASHRAE Standard 15 and/or any local building, fire or
mechanical codes. This applies to all units with either shell and tube con-
densers or high pressure relief valve options.
5.9

Commissioning

The system must be monitored after initial startup for a minimum of 60 minutes to ensure proper operat-
ing characteristics such as:
• Proper metering device operation and desired superheat readings
• Suction and discharge pressures are within acceptable levels
• Correct oil level in compressor sump indicating proper oil return
• Low foaming in sight glass and compressor sump temperature 10⁰ F above saturation
temperature to show there is no refrigerant migration taking place
• Acceptable cycling rates of compressors, including duration or run times
Short cycling protection is provided in the VFD. It is factory preset "enabled" with default
parameters. The minimum run time is set to ensure long enough running time at start up in
order to create enough refrigerant flow velocity in the system to recover the oil to the
compressor sump.
• Current draw of compressor within acceptable values
• No abnormal vibration or noise
Pressure relief lines(s) must be vented to the atmosphere per
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