York YD Mod D, Operation Manual, Page: 132 / 160

Warning messages
Table 140: Warning messages
Message Description
Warning – Condenser Or
Evaporator XDCR Error
The evaporator pressure transducer is indicating a higher pressure than the condenser
pressure transducer after the chiller has been running for 10 minutes. This is indicative
of a condenser or evaporator transducer failure. This message will be displayed until the
condition clears and the Warning Reset key is pressed in operator (or higher) access level.
Condition not checked in brine mode.
Warning – Condenser Or
VGD #1 Sensor Failure
The difference between compressor 1 stall pressure transducer output and the condenser
pressure transducer output has exceeded 0.28 VDC for 3 continuous minutes while
compressor 1 was running. This feature verifies the operation of compressor 1 stall
transducer and the condenser transducer. Since both transducers are measuring essentially
the same pressure, both outputs should be within the specified tolerance. This message
must be manually cleared. It will be displayed until the transducer outputs are within the
acceptable range of each other and the Warning Reset key in service access level.
While this message is displayed, the variable geometry diffuser (VGD) of both compressors
are driven to the full open position (100%) and held there until this warning is manually is
cleared. When cleared, the VGD of both compressors return to normal operation.
Warning – Condenser Or
VGD #2 Sensor Failure
The difference between compressor 2 stall pressure transducer output and the condenser
pressure transducer output has exceeded 0.28 VDC for 3 continuous minutes while
compressor 2 was running. This feature verifies the operation of the compressor 2 stall
transducer and the condenser transducer. Since both transducers are measuring essentially
the same pressure, both outputs should be within the specified tolerance. This message
must be manually cleared. It will be displayed until the transducer outputs are within the
acceptable range of each other and the Warning Reset key in service access level.
While this message is displayed, the variable geometry diffuser (VGD) of both compressors
are driven to the full open position (100%) and held there until this warning is manually is
cleared. When cleared, the VGD of both compressors return to normal operation.
Warning – Conditions
Override VGD #1
An extreme stall condition has been detected in compressor 1 while it was running. An
extreme stall condition exists when the stall detector voltage (output of the stall detector
board) exceeds twice the High Limit setpoint for the duration programmed in the
Extreme Stall Duration setpoint (10 to 20 minutes). While this message is displayed,
compressor #1 variable geometry diffuser is driven to the full open (100%) position and
held there until the message is manually cleared. This protects the VGD ring from possible
damage from an extreme stall condition. This message can be cleared after the stall detector
voltage returns to less than two times the High Limit setpoint and the Warning Reset key
is pressed in service access level.
The extreme stall condition is not checked under the following conditions:
• While the VGD is in manual control mode
• While the VGD is fully closed with position at 0% - VGD limit switch closed
• While the pre-rotation vanes position is greater than the PRV VGD Inhibit setpoint
Warning – Conditions
Override VGD #2
An extreme stall condition has been detected in compressor 2 while it was running. An
extreme stall condition exists when the stall detector voltage (output of the stall detector
board) exceeds twice the High Limit setpoint for the duration programmed in the
Extreme Stall Duration setpoint (10 to 20 minutes). While this message is displayed,
compressor 2 variable geometry diffuser (VGD) is driven to the full open (100%) position and
held there until the message is manually cleared. This protects the VGD ring from possible
damage from an extreme stall condition. This message can be cleared after the stall detector
voltage returns to less than two times the High Limit setpoint and the Warning Reset key
is pressed in service access level.
The extreme stall condition is not checked under the following conditions:
• While the VGD is in manual control mode
• While the VGD is fully closed with position at 0% - VGD limit switch closed
• While the pre-rotation vanes position is greater than the PRV VGD inhibit setpoint
Model YD Mod D with OptiView Control Center 132