Shutdown setpoint is enabled, when an excess surge condition is detected a safety shutdown is
performed and SURGE PROTECTION - EXCESS SURGE displays.
Head pressure control
The head pressure control feature enables chiller control of a field-mounted facility condenser
water temperature control means, if one is necessary for prolonged cold water startup as described
in OptiView Control Center functions and navigation. YMC
2
chillers are capable of operation
within a wide range of condenser water temperatures. However, a low minimum condenser
water temperature, as specified in the YMC
2
Engineering Guide, Form 160.84-EG1, is required to
maintain sufficient pressure differential (head) between the condenser and evaporator for correct
refrigerant management in the chiller. The head pressure control function provides an analog
output control signal from the OptiView
™
control center that responds to the programmed head
pressure (condenser pressure minus evaporator pressure) setpoint. The 0-10 VDC or 4-20 mA
output is configurable from the head pressure control screen when the feature is enabled. Output
wiring is described in the Field Connections section of the Wiring Diagram, Form 160.84-PW2 and
PW4.
19
YMC
2
Mod B with OptiView Control Center
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