York YST Operation Manual page 144

SECTION 2 - OPTIVIEW CONTROL CENTER INTRODUCTION
ergized. This message is also displayed if the standby
sealing water flow switch opens while the associated
solenoid is energized indicating a possible failure of
the solenoid coil. This message also appears when MS-
SP11-Vacuum Pump Mode is set for Single or Ejector
and a failure occurs. The START/STOP control switch
must be placed in the STOP-RESET (O) position be-
fore starting the chiller.
"vacuum pump fault"
When MSSP11-Vacuum Pump Mode on Configuration
Screen 1 is set for Dual, this message appears when the
lead vacuum pump has failed and the standby vacuum
pump start has been initiated. The standby sealing wa-
ter flow switch has not closed within 10 seconds after
the associated solenoid has been energized or the lead
vacuum pump contactor auxiliary contact has failed to
close within 5 seconds after the run output was ener-
gized to start the pump. This message is also displayed
if the standby sealing water flow switch opens while
the associated solenoid is energized indicating a pos-
sible failure of the solenoid coil. This message also
appears when MSSP11-Vacuum Pump Mode is set for
Single or Ejector and a failure occurs. The START/
STOP control switch must be placed in the STOP-RE-
SET (O) position before starting the chiller.
"Turbine underspeed"
There fault conditions that will display this message
are as follows:
• Failure to Achieve Slow Roll Speed: The turbine
has begun rotating but has not achieved the SSP1-
Slow Roll Setpoint speed shown on the Speed
Setpoints Screen within the TDSP16-Slow Roll
Underspeed Timeout delay shown on the Time
Delay Alarm/Shutdown Setpoints Screen.
• Failure to Maintain Slow Roll Speed: The tur-
bine speed has been continuously running at a
speed that is less than the SSP1-Slow Roll Setpoint
minus 100 RPM for longer than 60 seconds.
• Failure to Ramp Achieve Minimum Rated
Speed: During ramp up to rated speed, the turbine
been running within the critical speed band for
longer than 17 seconds. The critical speed band is
determined by the values entered for SSP11 and
SSP12 on the Speed Setpoints Screen.
144
• Failure to Maintain Minimum Rated Speed:
The turbine has been continuously running at a
speed below 3100 RPM for longer than 20 sec-
onds.
• The START/STOP control switch must be placed
in the STOP-RESET (O) position before starting
the chiller.
"Steam valve Malfunction"
The Turbine Rotating (Speed Switch) contacts are
closed or a speed sensor analog input is greater than
20 RPM without the Turbine Trip Valve Air Dump So-
lenoid being energized. This indicates that the turbine
has begun rotating due to a possible steam leak through
the trip valve. The drive train willl normally coast to a
complete stop within 6 minutes after a shutdown. After
0 RPM is detected, this safety is enabled until a start is
initiated and the speed setpoint is increased to open the
Governor Valve and begin rotation. The START/STOP
control switch must be placed in the STOP-RESET (O)
position before starting the chiller.
" Turbine – Supply oil Temperature out of
range"
This message only applies when the turbine is sup-
plied with an auxiliary oil pump and MSSP6-Turbine
Lubrication Type is set for Pump on the Configuration
Screen 1. It appears when the input signal from the
Turbine Supply Oil RTD Temperature Transmitter is
below 32 °F. This is outside the normal operating range
and generally indicates a defective transmitter or RTD
sensing element. The chiller can only be started after
the transmitter input is indicating a temperature that is
within range and the START/STOP control switch is
placed in the STOP-RESET (O) position.
An input signal above 302 °F would also
indicate a defective transmitter or RTD
sensing element but will generate a nor-
mal safety shutdown message since this
value exceeds the safety setpoint.
"Turbine – Supply oil high Temperature"
This message only applies to when the turbine is sup-
plied with an auxiliary Oil Pump and MSSP6-Turbine
Lubrication Type is set for pump on the Configura-
tion Screen 1. It appears when the input signal from
the Turbine Supply Oil RTD Temperature Transmitter
is above the TSP9-Turbine Supply Oil High Tempera-
ture Shutdown setpoint shown on the Alarm/Shutdown
FORM 160.67-O1
ISSUE DATE: 4/1/2015
JOHNSON CONTROLS