JOHNSON CONTROLS
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SECTION 2 - OPTIVIEW CONTROL CENTER INTRODUCTION
FORM 160.78-O2
ISSUE DATE: 5/22/2017
2
MESSAGE DESCRIPTION
EVAPORATOR – TRANSDUCER
OR TEMPERATURE SENSOR
A possible defective Evaporator pressure Transducer or Refrigerant Temperature Sen-
sor has been detected. The control center converts the evaporator pressure to a Satu-
rated Temperature value and compares this value to the optional Evaporator Refrigerant
Temperature Sensor. If the difference between these temperatures is greater than 3.0°F,
continuously for 1 minute, this shutdown is performed. This check is only performed
under the following conditions:
• Chiller has been running for at least 10 minutes
• Evaporator Refrigerant temperature (RT7) has been enabled by a Service technician
using instructions in YORK YMC
2
Service Manual (Form 160.78-M2).
• 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 (0°C).
The chiller can be started after the temperatures are within 3.0°F (1.77°C) of one an-
other and the CLEAR FAULT key is pressed.
MBC – CABLE FAULT
This Safety Shutdown is set when the MBC does not detect continuity expected through
a set of supervisory pins through an embedded jumper in either of the two main electri-
cal cable assemblies. The MBC ESD Fault contacts open. The MBC remains in Levi-
tation mode with the motor shaft levitated until commanded to de-levitate over serial
comms or VSD DC buss power depletes. This shutdown is released when the connector
to cable supervisory jumper continuity is restored. The chiller can be started when the
condition is released and the Optiview panel CLEAR FAULTS key is pressed.
MBC – CUSTOMER SERIAL
LINK DISABLED
This Safety Shutdown is set when the MBC Local/Remote Modbus command is not
reported from the MBC as set for panel control. This would be caused if the MBC were
accessed via a computer using diagnostic software and the serial communication set-
ting then changed in the Remote Command tab from Customer Serial Link to another
choice. The chiller can be started when the MBC setting is restored to Customer Serial
Link using the diagnostic software according to Form 160.78-M1 and the OptiView panel
CLEAR FAULTS key is pressed.
MBC – DATA ACQUISITION
FAULT
This Safety Shutdown is set when the MBC detects an internal communication problem
on the AMB control board. The MBC ESD Fault contacts open. The MBC remains in
Levitation mode with the motor shaft levitated until commanded to de-levitate over serial
comms or VSD DC buss power depletes. This shutdown is released when the MBC rec-
ognizes proper internal communication after a reboot. The chiller can be started when
the condition is released and the OptiView panel CLEAR FAULT key is pressed.
MBC – DSP COMMUNICATION
This Safety Shutdown is set when the MBC control board detects a communication
error across circuit boards in the MBC. The MBC ESD Fault contacts open. The MBC
remains in Levitation mode with the motor shaft levitated until commanded to de-levitate
over serial comms or VSD DC buss power depletes. This shutdown is released when
the board-level communication failure is resolved. The chiller can be started when the
condition is released and the OptiView panel CLEAR FAULTS key is pressed.
MBC – DSP INITIALIZATION
This Safety Shutdown is set when the MBC control board software fails to initialize.
The MBC is determining software parameters are not correct. The MBC ESD Fault
contacts open. The MBC remains in Levitation mode with the motor shaft levitated until
commanded to de-levitate over serial comms or VSD DC buss power depletes. The
condition may require reloading the control parameters to the control. The condition
is released on a successful re-boot. The chiller can be started when the condition is
released and the OptiView panel CLEAR FAULTS key is pressed.
MBC – DSP INTEGRITY
This Safety Shutdown is set when an internal problem occurs on the AMB control board.
The MBC remains in Levitation mode with the motor shaft levitated until commanded to
de-levitate over serial comms or VSD DC buss power depletes. This shutdown is released
when the board-level communication failure is resolved. The chiller can be started when
the condition is released and the OptiView panel CLEAR FAULTS key is pressed.
TABLE 9 - SAFETY SHUTDOWN MESSAGES (CONT'D)
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