48
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. A system charged to a clear sight glass is
often overcharged.
When charging is complete, close the valve on the refrigerant manifold set and close the service valve
on the refrigerant tank. Then go back into menu “H. Calibrate Sensors” and set either the “Return Air
Temp Sensor” or “Discharge Air Temp Sensor” menu offset values back to 0. If a calibration offset value
has been determined in the field that is different from 0 bring the offset number back to this value.
5.6 Water/Glycol System
5.6.1 Water/Glycol Cooled System Charging
All water/glycol cooled units are factory charged with refrigerant. The water regulating valve should
be adjusted to maintain the required conditions. Field charging, if required, of water/glycol systems
should be done by referring to the unit’s electrical nameplate. The factory charge is indicated on the
nameplate. Although this figure represents the initial factory charge, it is still necessary to measure
and note proper unit operation including superheat, head and suction pressure. Some adjustment of
charge may be required.
Adjust the refrigerant charge until the sight glass clears or has sparse bubbles. The system should
be allowed to stabilize for 15 to 20 minutes before meaningful measurements can be taken. After the
system is allowed to stabilize, verification of a few key measurements should be noted.
Function
R-410A Conditions
Condensing Temperature
105 to 119⁰F (41 to 48⁰C)
Saturated Suction Temperature
33⁰F (0.6⁰C) or higher
Superheat
8 to 15⁰F (4.44 to 8.33⁰C) Differential
The superheat at the compressor suction line at least 6 inches (152 mm) away from the compressor.
All water/glycol cooled units have a water regulating valve. A head pressure transducer is connected
to a Schrader fitting on the discharge line and water is regulated into the condenser coil (plate fin con
-
densers are standard).
WARNING:
Before starting a compressor, the crankcase heater should be
energized for a minimum of 12 hours to reduce the possibility of liquid slug-
ging on start-up. Failure to energize the crankcase heater could result in
compressor damage. If the system is charged from a vacuum, the preheat-
ing of the compressor is not necessary.
Summary of Contents for gForce Ultra
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