Refrigerant And Oil Charge Management - Trane R Series Installation, Operation And Maintenance Manual

Maintenance
Refrigerant and Oil Charge
Management
Proper oil and refrigerant charge is essential for proper
unit operation, unit performance, and environmental
protection. Only trained and licensed service personnal
should service the chiller.
Some symptoms of a refrigerant under-
charged unit:
• Low subcooling
• Higher than normal discharge superheat
• Bubbles in EXV sight glass
• Low liquid level diagnostic
• Larger than normal evaporator approach
temperatures (leaving water temperature - saturated
evaporator temperature)
• Low evaporator refrigerant temperature limit
• Low refrigerant temperature cutout diagnostic
• Fully open expansion valve
140
• Possible whistling sound coming from liquid line (due
to high vapor velocity)
• High condenser + subcooler pressure drop
Some symptoms of a refrigerant over-charged
unit:
• High subcooling
• Evaporator liquid level higher than centerline after
shut down
• Larger than normal condenser approach temperatures
(entering condenser saturated temperature – entering
air temperature)
• Condenser pressure limit
• High pressure cutout diagnostic
• More than normal number of fans running
• Erratic fan control
• Higher than normal compressor power
• Very low discharge superheat at startup
• Compressor rattle or grinding sound at startup
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