York YK-EP Operation And Maintenance Manual page 210

• Evaporator Refrigerant Temperature (RT7) has been enabled by a Service Technician using
instructions in OptiView Control Center – Service Instructions (Form 160.54-M1)
• Not in Brine Cooling mode
• Smart Freeze is enabled.
• Evaporator Temperature Sensor (RT7) or Evaporator Saturation Temperature is indicating a
temperature of less than 32.0°F
The chiller can be started after the temperatures are within 3.0°F of one another and the Operator
presses the WARNING RESET button.
Condenser – High Pressure Contacts Open
The contacts of the electro-mechanical high pressure safety device, located on the condenser shell,
have opened because this device has detected a pressure:
• more than 204 PSIG (R134a)
The contacts will automatically close when the condenser pressure decreases to:
• less than 160 PSIG (R134a)
The chiller can be started after the contacts close and the Operator presses the WARNING RESET
button.
Condenser – High Pressure
The condenser pressure, as sensed by the Condenser transducer, has increased to:
• more than 180.0 PSIG (R134a)
• more than 265.0 PSIG (R22)
The chiller can be started after the pressure decreases to:
• less than 120.0 PSIG (R134a)
• less than 205 PSIG (R22) and the Operator presses the WARNING RESET button.
For special order R134a high condenser temperature chiller applications, the Condenser
Temperature Range Setpoint is set to Extended. The trip/reset threshold is then 200/140 PSIG.
Condenser – High Pressure – Stopped
The condenser pressure exceeded 160.0 PSIG (R134a), 240.0 PSIG (R22) while the chiller was
stopped. High temperature condenser water flowing through the condenser while the chiller is
shutdown can cause a condenser high pressure condition resulting in loss of refrigerant. This safety
fault anticipates this problem by annunciating the condenser high pressure condition. The chiller
can be restarted after a Service Technician performs a special reset preset procedure contained in
OptiView Control Center – Service Instructions (Form 160.54-M1).
For special order R134a high condenser temperature chiller applications, the Condenser
Temperature Range Setpoint is set to Extended. The trip/reset is then 170/170 PSIG .
Condenser – Pressure Transducer Out Of Range
The Condenser Pressure transducer is indicating a pressure that is:
• less than 6.8 PSIG (R134a)
• less than 24.2 PSIG (R22)
• or more than 300.0 PSIG (R134a or R22)
210 YK-EP Style B Centrifugal Chiller