JOHNSON CONTROLS
116
FORM 160.78-O2
ISSUE DATE: 5/22/2017
SECTION 2 - OPTIVIEW CONTROL CENTER INTRODUCTION
TABLE 6 - WARNING MESSAGES
MESSAGE DESCRIPTION
WARNING – MBC – LANDING
COUNTER HIGH
The MBC landing counter has accumulated 30 events where the motor shaft displace-
ment exceeded 120 µm (80% of the air gap space to the touchdown bearing) while shaft
rotation is detected. This warning is released only when a service technician checks
the shaft air gap measurement for acceptability and resets the MBC according to the
driveline service manual YORK YMC
2
Service Manual (Form 160.78-M2).
WARNING – MBC – ROTATION
MODE OFF
During the time the MBC Rotation Mode is commanded ON by the microboard via serial
comms this warning is set if the MBC reports Rotation Mode is OFF by serial comms.
This warning is inhibited if MBC communication is not initiated and during the rst 15
seconds after the Rotation Mode is commanded ON. This warning is released when
Rotation Mode status matches the microboard command to the MBC.
WARNING – MOTOR – HIGH
CURRENT LIMIT
The chiller motor current is greater than or equal to the Motor Overload current limit.
The Motor Overload current limit is predetermined from the motor model and Maximum
VSD Output Current. While this condition is in effect, chiller capacity control is in over-
ride to reduce current. Normal LCHLT capacity control operation is resumed and this
message automatically clears when the motor current decreases below this limit.
WARNING – CONDENSER –
HIGH PRESSURE LIMIT
The Condenser Pressure exceeds the High Pressure Warning Setpoint threshold,
programmed by a Service technician logged in at SERVICE access level. While this
condition is in effect, the chiller capacity is in override to reduce pressure. This message
automatically clears and normal LCHLT capacity control restored when the Condenser
pressure decreases to below the Setpoint.
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 Keypad key is pressed in OPERATOR
(or higher) access mode. Condition not checked in Brine mode.
WARNING – CONDENSER OR
VGD SENSOR FAILURE
The difference between the Stall Pressure Transducer output (discharge pressure) and
the Condenser Pressure Transducer output has exceeded 0.28 VDC for 3 continuous
minutes while the chiller was running. This feature veries the operation of the Stall
Transducer and the Condenser transducer. Since both transducers are measuring es-
sentially the same pressure, both outputs should be within the specied 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) is driven to the
full open position and held there until this warning is manually cleared. When cleared,
the VGD returns normal operation.
WARNING – EVAPORATOR –
LOW PRESSURE LIMIT
The Evaporator pressure has decreased to the Warning threshold. This threshold is
xed in Water cooling applications. In Brine cooling applications, the threshold is a xed
amount above the programmable safety shutdown threshold. The Safety threshold in
Brine applications is determined by the Brine solution and is determined by the YORK
Factory. While this condition is in effect, the chiller capacity control is in override to in-
crease suction pressure. This message automatically clears and normal LCHLT capacity
control restored when the Evaporator pressure increases to the reset value.
EVAPORATOR PRESSURE THRESHOLDS
Warning Threshold
(PSIG)
Reset Threshold
(PSIG)
Water Brine Water Brine
R134a 27.0
+2.0>Safety
Setpoint
28.0
+3.0>Safety
Setpoint
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