Data Aire DA PA-04, Инструкция по установке, эксплуатации и обслуживанию

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NOTICE: 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, subcooling and ambient
temperature are also important. A system charged to a clear sight glass is
often overcharged.
WARNING: Avoid trapping refrigerant in sections where hydrostatic
pressure can develop. If refrigerant can be trapped in part of the system,
a liquid line relief valve may be required.
Flooded systems are supplied with an optional liquid receiver and head pressure control valve. When
the ambient temperature falls during cold weather, the head pressure control valve will regulate the
flow of refrigerant to ensure minimum receiver pressure. The subcooling, at times, will fluctuate. The
condenser is partially flooded with liquid refrigerant in cold weather. In warm weather, the extra
refrigerant is stored in the receiver.
Flooded systems require more refrigerant than units with fan speed
control units.
Refrigerant Receiver
The function of a Liquid Refrigerant Receiver is to store liquid refrigerant to provide continuous flow of
liquid refrigerant to the expansion device and to provide storage for the refrigerant charge during system
service or maintenance.
A receiver is required to store refrigerant during warmer weather. The receiver should be sized so it is
at 80 to 82% of capacity while containing the entire system charge. Another aspect of receivers is that
they contain both liquid and gaseous refrigerant at the same time. By their design, receivers prohibit
liquid subcooling from occurring. Without liquid subcooling the capacity of the system is reduced, and
care must be taken in the design of the liquid line to avoid flashing at the expansion valve.
Flooded systems are an excellent method of providing head pressure control in cold climates, but they
increase initial cost, add complexity to the refrigeration system, increase installation time, and increase
the refrigerant charge. The loss of subcooling should be recognized. If a flooded system is required,
consult the Data Aire prior to installation.
Applications
Liquid Refrigerant Receivers are installed in air conditioning and refrigeration systems. The receiver is
installed after the condenser in order to collect the condensed refrigerant to allow a continuous liquid
supply to the expansion device. Liquid receivers are also used to store the refrigerant charge while the
system is pumped down for service or maintenance.
Selection Guidelines
Receiver storage capacities are based on the liquid occupying no more than 90% of the internal volume
when the temperature of the refrigerant is 90°F (32°C) per ASHRAE Standard 15-78. Includes within
Data
Aire’ Product Selector Guide, the low ambient receiver package has already sized and selected
for each Ultra model size.