York YST Operation Manual page 143

FORM 160.67-O1
ISSUE DATE: 4/1/2015
" Compr Thrust bearing – proximity probe
out of range"
The clearance between the compressor high speed
thrust collar and the tip of the Proximity Probe has de-
creased to < 17 mils.
This shutdown must be evaluated by a
qualified Service Technician prior to start-
ing the chiller. Starting the chiller without
this evaluation could result in severe
compressor damage. To prevent the chiller
from starting without the proper evalua-
tion, restart is inhibited until the clearance
is within +10 to -25 mils of the Reference
Position and a special reset procedure is
performed by the Service Technician.
"Mpu failure"
This message will appear if the chiller is being oper-
ated with only one magnetic pickup and the remaining
input signal drops 1.0 mA below the calibrated mini-
mum input signal which generally indicates a defective
frequency to analog converter. The chiller can only be
started after at least one of the speed input signals is
within the calibrated range and the START/STOP con-
trol switch is placed in the STOP-RESET (O) position.
" Turbine exhaust Steam high pressure"
The input signal from the Turbine Exhaust Steam Pres-
sure Transmitter has been above the PSP7-Turbine
Exhaust Steam High Pressure setpoint shown on the
Alarm/Shutdown Setpoints Screen for the TDSP7-
Turbine Exhaust High Pressure Timeout delay shown
on the Time Delay Alarm/Shutdown Setpoints Screen.
This check is bypassed until the chiller is in the System
Run Mode. The START/STOP control switch must be
placed in the STOP-RESET (O) position before start-
ing the chiller.
"Turbine Mechanical Trip"
The Turbine Trip Valve Air Dump Solenoid is ener-
gized but the Turbine Trip Valve Limit Switch contact
is open indicating that the trip valve has not opened or
has been closed by the hand trip knob on the turbine, a
mechanical over-speed trip, a failure of the pneumatic
air supply, or a mechanical valve actuator failure. This
check is bypassed until the TDSP15-Turbine Mechani-
cal Trip timeout delay shown on the Time Delay Alarm/
Shutdown Setpoints Screen has elapsed after the Tur-
bine Trip Valve Air Dump Solenoid is energized. The
START/STOP control switch must be placed in the
STOP-RESET (O) position before starting the chiller.
JOHNSON CONTROLS
SECTION 2 - OPTIVIEW CONTROL CENTER INTRODUCTION
"excessive Start delay"
The system prelube has been completed but the opera-
tor has failed to press the Begin Slow Roll key on the
Steam System Screen to initiate the slow roll warm-
up within the TDSP8-Excessive Start Delay Timeout
delay shown on the Time Delay Alarm/Shutdown
Setpoints Screen. The START/STOP control switch
must be placed in the STOP-RESET (O) position be-
fore starting the chiller.
"excessive Slow rolling Trip"
The turbine has been slow rolling longer than the cal-
culated slow roll warm-up time plus the TDSP1-Ex-
cessive Slow Roll Timeout delay shown on the Time
Delay Alarm/Shutdown Setpoints Screen. This indi-
cates that the operator has failed to press the "Run At
Rated" key that appears on the Steam System Screen to
close the Chilled Liquid Pump Start contacts and initi-
ate the ramp up to rated speed. When MSSP4-Turbine
Start Mode is set for Auto on Configuration Screen 1,
this would indicate that the vacuum pump has failed to
reduce the turbine exhaust pressure to the PSP6-Ready
To Run pressure shown on the Pressure Setpoints
Screen, thereby preventing the automatic ramp up to
rated speed. The START/STOP control switch must be
placed in the STOP-RESET (O) position before start-
ing the chiller.
"hotwell pump fault"
When MSSP10-Hotwell Pump Mode on Configuration
Screen 1 is set for Dual, this message appears when
the lead hotwell pump has failed, the standby pump
start has been initiated, but the standby hotwell pump
contactor auxiliary contact has failed to close within 5
seconds after the run output was energized to start the
pump. This message is also displayed if the auxiliary
contact opens anytime the run output is on indicating
that the pump motor protector in the Power Panel may
have stopped the pump. This message also appears
when MSSP10-Hotwell Pump Mode is set for Single
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 Sealing Water no flow"
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 standby pump sealing water solenoid has been en-
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