18 • Air Cooled Condenser User Manual
NOTE: Charging to a full liquid line sight-glass should never be the sole means of de-
termining the correct refrigerant charge. Other parameters such as superheat, suction
pressure, head pressure, sub-cooling and ambient air temperature are also important.
A system charged to a full sight-glass is often overcharged.
4.3.1 R-410a – Charging/Installation Work Procedures
The basic installation work procedures are the same as R-407c refrigerant. Since the working pres-
sure is 1.6 times higher than the conventional refrigerant, some of the piping, installation and tools
are special.
Special Service Equipment
• High pressure manifold gauge set
• High pressure recovery machine
• High pressure recovery tank (DOT 4BA400 or ABW400)
NOTE: R-410a and R-407c use Polyolester oil (POE) oil that is prone to absorbing
moisture. The system should never be left open to the atmosphere.
4.4 Flooded Systems
Flooded systems are units having refrigerant circuits with optional liquid receiver and head pressure
control (recommended for low ambient conditions). When the ambient temperature falls during cold
weather, the head pressure control valve will regulate the flow of refrigerant to ensure nearly con-
stant receiver pressure. The condenser is partially flooded with liquid refrigerant in cold weather. In
warm weather the extra refrigerant is stored in the receiver.
Data Aire units with optional receivers are either provided within the evaporator section (depending
on the unit size) or shipped loose for eld installation. The receiver includes heaters and thermostat.
A thermostat monitors temperature in the receiver and prevent overheating (overheating of receiv-
ers may cause the soft plug to blow and loss of refrigerant charge).
4.4.1 Charging Flooded Systems
Flooded systems require more refrigerant than condensers with fan speed control. With the unit
under a vacuum, add liquid refrigerant directly into the receiver. Make sure all hoses are properly
purged.
Use the manual override switches (evaporator motor and compressor) on the unit mounted control-
lers (dap4, DAP-III or DAP-II) to switch the units to the ON position (all automatic control will be
disabled but safety switches will remain functional).
Hook up charging gauges to the suction line. If the receiver (head) pressure is below the pressure
shown in the chart below for the required refrigerant, block part of the condenser coil surface until
the pressure rises to the specied pressure or higher. During extremely cold weather all the con-
denser fans may have to be de-energized to maintain the desired receiver (head) pressure.
Refrigerant Receiver (Head) Pressure
R-410a 342 PSIG
R-407c 242 PSIG 10
Observe the sight-glass on the receiver. Add refrigerant liquid through the suction line until the level
of liquid in the receiver is approximately 1/3 from the bottom of the sight-glass which is about 80%
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