Figure 39. Cutout strategy
Chilled-Water Set Point
Differential to stop
adjustment range
X degrees minimum differential
Y degrees minimum
differential
Evaporator leaving-water
temperature cutout
Evaporator refrigerant
temperature cutout
Hold
Evaporator
limit
Integrate to trip
Evaporator limit set point
Limit loading
Unload
2°F (1.1°C)
0.5°F (0.28°C)
2.5°F (1.36°C)
Condenser Limit
Condenser pressure is continuously monitored to provide a limit function that pre-
vents High Pressure Cutout (HPC) trips. This protection is called Condenser Refrigerant
Pressure Limit, or High Pressure Limit. A fully loaded compressor, operating at high
Evaporator Leaving Water Temperature (ELWT) and high condenser temperatures
causes high condenser pressures. The purpose of this limit is to avoid HPC trips by al-
lowing the chiller to continue to run at a lower load instead of tripping off using HPC.
The Condenser Limit will be based on a pressure conversion from the Condenser Re-
frigerant Temperature sensor. When limited by this action, “Condenser Pressure Limit”
will be displayed as a sub-operating mode.
The Condenser Limit Setpoint is factory set (93 percent of HPC), however can be
changed using Tracer ™.
CVGF-SVX03B-EN
108
Machine Protection and Adaptive Control
Summary of Contents for CVGF1000
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