Installation, Operation and Maintenance Manual
4 Charging
As a minimum, the servicing technician should wear thermal protective gloves and face-shield/goggles when
working with refrigerant.
NOTICE Application of excessive heat to any component will cause extreme
pressure and may result in a rupture. Exposure of refrigerant to an open flame
or a very hot surface will cause a chemical reaction that will form a highly
poisonous and corrosive gas commonly referred to as PHOSGENE.
In its natural state, refrigerant is a colorless, odorless vapor. It is heavier than air and will disperse rapidly in a well-
ventilated area. In an unventilated area, it presents a danger.
Air Cooled Systems
4.1.1 Packaged Air-Cooled Systems Ceiling Units (2.5 to 5 Ton)
Packaged air-cooled units come factory charged because all the refrigerant carrying components are self-contained
with the evaporator and condenser sections.
WARNING Before starting a compressor, the crankcase heater should be
energized for a minimum of 12 hours to reduce the possibility of liquid slugging
on start-up. Failure to energize the crankcase heater could result in compressor
damage. If the system is charged from a vacuum, the preheating of the
compressor is not necessary.
When starting-up the equipment, it is the responsibility of the field service technician to verify that the system is
properly charged. A properly charged R-410A system operating at typical parameters will have the following
pressures:
Typical Operating Parameters
Superheat (at the compressor suction line)
An air-cooled package unit may require field charging if a compressor is changed if a leak develops or if non-
condensable are in the system. Field charging should be done by referring to the unit electrical nameplate for the
factory charge.
Although this value represents the original factory charge, it is still necessary to measure and note proper unit
operation including superheat, sub-cooling, head and suction pressure. Some adjustment to charge may be
required.
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