Water/Glycol Cooled Systems; Water/Glycol Cooled Systems Charging; Refrigerant Handling; Important Refrigeration Components - Data Aire LCS Installation, Operation And Maintenance Manual

5.3

Water/Glycol Cooled Systems

5.3.1. Water/Glycol Cooled Systems Charging

All water/glycol cooled units are factory charged with refrigerant. The water regulating valve should
be adjusted to maintain condensing temperature of 105 - 119° F. Saturated suction temperature
should be 33° F or higher. The superheat at the compressor suction line at least 6 inches away from
the compressor should be 8-15° F.
Field charging water/glycol systems should be done by referring to the unit electrical nameplate for
the factory charge. Although this fi gure represents the original factory charge, it is still necessary
to measure and note proper unit operation including superheat, head and suction pressure. Some
adjustment to charge may be required.
Adjust the refrigerant charge until the sight glass clears or has only sparse bubbles. The unit should
be allowed to stabilize for several minutes before meaningful measurements can be taken and the
conditioned room should be at or near the temperature setpoint.
All water/glycol cooled units have a water regulating valve. A head pressure sensing transducer is
connected to a shrader fi tting on the discharge line and water is regulated into the condenser coil.
Condenser coils may be plate fi n or coaxial type.
Before starting a compressor, the crankcase heaters should be energized for a minimum
of 12 hours to reduce the possibility of liquid slugging on start-up. Failure to energize
crankcase heaters could result in compressor damage.
Note: Charging to a full liquid line sight glass should never be the sole means of
determining the correct refrigerant charge. Other parameters such as superheat, suction
pressure, head pressure, sub-cooling and ambient temperature are also important
parameters. A system charged to a clear sight glass is often overcharged.
5.4

Refrigerant Handling

The 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 equipment
must recover the refrigerant instead of venting to atmosphere.
Except for extremely small releases of refrigerant such as what occurs when disconnecting service
hoses (diminutive release), a technician who knowingly releases or vents refrigerant to the atmosphere
is in violation of these regulations. Freon purchasers must be certifi ed technicians and have a valid
EPA certifi cation card.
5.5

Important Refrigeration Components

5.5.1. Expansion Valve

Each refrigerant circuit has an adjustable thermo-expansion valve (TXV). These are factory adjusted
to their nominal rating. Any fi eld adjustment should be to fi ne tune a system that has stabilized and
already has acceptable operating parameters.
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