Data Aire LCS Installation, Operation And Maintenance Manual

Also see for DAFC 06: Installation, operation and maintenance manual Installation, operation and maintenance manual Installation, operating and maintenance manual

Data Aire LCS Installation, Operation And Maintenance Manual Manual pdf 23 page image

235.3 Water/Glycol Cooled Systems5.3.1. Water/Glycol Cooled Systems ChargingAll water/glycol cooled units are factory charged with refrigerant. The water regulating valve shouldbe adjusted to maintain condensing temperature of 105 - 119° F. Saturated suction temperatureshould be 33° F or higher. The superheat at the compressor suction line at least 6 inches away fromthe compressor should be 8-15° F.Field charging water/glycol systems should be done by referring to the unit electrical nameplate forthe factory charge. Although this figure represents the original factory charge, it is still necessaryto measure and note proper unit operation including superheat, head and suction pressure. Someadjustment to charge may be required.Adjust the refrigerant charge until the sight glass clears or has only sparse bubbles. The unit shouldbe allowed to stabilize for several minutes before meaningful measurements can be taken and theconditioned room should be at or near the temperature setpoint.All water/glycol cooled units have a water regulating valve. A head pressure sensing transducer isconnected to a shrader fitting on the discharge line and water is regulated into the condenser coil.Condenser coils may be plate fin or coaxial type.Before starting a compressor, the crankcase heaters should be energized for a minimumof 12 hours to reduce the possibility of liquid slugging on start-up. Failure to energizecrankcase heaters could result in compressor damage.Note: Charging to a full liquid line sight glass should never be the sole means ofdetermining the correct refrigerant charge. Other parameters such as superheat, suctionpressure, head pressure, sub-cooling and ambient temperature are also importantparameters. A system charged to a clear sight glass is often overcharged.5.4 Refrigerant HandlingThe use of recovery/recycling units is required by U.S. Environmental Protection Agency (EPA)regulations. Technicians who service and dispose of air conditioning and refrigeration equipmentmust recover the refrigerant instead of venting to atmosphere.Except for extremely small releases of refrigerant such as what occurs when disconnecting servicehoses (diminutive release), a technician who knowingly releases or vents refrigerant to the atmosphereis in violation of these regulations. Freon purchasers must be certified technicians and have a validEPA certification card.5.5 Important Refrigeration Components5.5.1. Expansion ValveEach refrigerant circuit has an adjustable thermo-expansion valve (TXV). These are factory adjustedto their nominal rating. Any field adjustment should be to fine tune a system that has stabilized andalready has acceptable operating parameters.