ARTC-SVX001B-EN
43
N
NO
OT
TIIC
CE
E
P
Prro
oo
off o
off F
Fllo
ow
w S
Sw
wiittcch
h!!
F
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viid
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ess o
orr jju
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utt o
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me
en
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da
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E
Ev
va
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••
F
Fa
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prro
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off
tth
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hiilllle
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Phase Monitor
A compressor can fail if operated in reverse for more
than a minute. A phase monitor is used on three phase
power systems to ensure that the electricity supplying
the chiller is configured appropriately. A phase monitor
prevents a motor from operating in reverse—if any of
the three legs of power are landed incorrectly—and will
shut the system down upon detection of a reversed
phase condition.
Refrigeration Controls
Controls on the refrigeration system are designed to
provide safety for the major components and for
proper operation of the system.
Pressure transducers convert pressure into an
electronic signal that the microprocessor displays in
pounds per square inch (psi). Transducers vary in
pressure ranges that depend on the type of refrigerant
used. Pressure transducers are calibrated using the
interface panel.
Temperature sensors transmit temperature data
electronically to the microprocessor for display in
either Fahrenheit (°F) or Celsius (°C). Temperature
sensors are calibrated using the interface panel.
Expansion Valve
An expansion valve is a metering device controlling the
flow of refrigerant to the evaporator based on
evaporator superheat.
Superheat is factory-set for around 12 °F (-11 °C). Close
the valve to increase superheat. To accurately read
superheat, install a temperature sensor at the
evaporator outlet. The sensor bulb should be located at
the 4 o’clock or 8 o’clock positions on the pipe for the
most accurate pressure measurement.
Ensure that the closed cell insulation covers the
thermal expansion valve sensing bulb. If insulation is
missing, the bulb will tend to feed more refrigerant to
satisfy the superheat setting.
Solenoid Valve
The liquid-line solenoid valve is used in the
refrigeration cycle to provide a refrigerant pump-down
cycle at the end of a compressor’s cycle. The liquid
refrigerant is pumped out of the evaporator to
eliminate liquid refrigerant from migrating to the
compressor in the off cycle.
Sight Glass
When the sight glass shows a green indicator, no
moisture is present. When the sight glass shows a
yellow indicator, there is moisture in the refrigerant
line. Bubbles can be observed whenever chiller cycling
causes the pressure to change up or down.
