AERCO BMS 168 - Manual (Page 72)

H-2
Appendix H
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Table H1 Error Messages - Continued
Fault Message Description & Possible cause
SYSTEM ERROR,
INTERLOCK 2 OPEN
Interlock 2 is open
(4-20 MA) INPUT
OPEN LOOP ERROR
The 4-to-20-mA remote input signal has dropped below 3 mA, or the
signal is not present at the BMS.
FAIL SAFE MODE
ACTIVATED
This message can be displayed when the BMS is controlling the
boilers via Modbus or PWM communication. It indicates that the BMS
is operating in the Fail Safe (Constant Setpoint) mode.
NETWORK COMM FLT
TIMEOUT ERROR
Displayed during Modbus Remote Setpoint operation when the BMS is
functioning as a Slave to an EMS Master. Error indicates that the
Network Timeout has expired.
NETWORK DISABLED
MODBUS LISTEN
Displayed during Modbus operation when the “FORCE LISTEN
ONLY” Modbus diagnostic command is sent to the BMS Slave by the
controlling Master, thereby disabling normal Modbus Network
communication. It indicates that the Master is listening for the
“RESTART COMMUNICATIONS OPTIONS” diagnostic command
required to restart normal Modbus communication. The BMS will
operate in the Fail Safe mode during this period.