Appendix b – AERCO KC1000 Boiler equipped with C-More version 3.04 User Manual
Page 79

APPENDIX B
B-3
TABLE B-2. FAULT MESSAGES - Continued
FAULT MESSAGE
FAULT DESCRIPTION
OUTDOOR TEMP
SENSOR FAULT
The temperature measured by the Outdoor Air Sensor is out 
of range. 
OUTLET TEMP
SENSOR FAULT
The temperature measured by the Outlet Sensor is out of 
range: 
• OUTLET TEMPERATURE display = SHt Indicates sensor 
is shorted
• OUTLET TEMPERATURE display = OPn indicates sensor
is open-circuited
PRG SWTCH CLOSED
DURING IGNITION
The Purge Position Limit Switch on the Air/Fuel Valve closed 
during ignition. 
PRG SWTCH OPEN
DURING PURGE
The Purge Position Limit Switch on the Air/Fuel Valve 
opened during purge. 
REMOTE SETPT
SIGNAL FAULT
The Remote Setpoint signal is not present or is out of range.
RESIDUAL
FLAME
The Flame signal was seen for more than 60 seconds during 
standby. 
SSOV
SWITCH OPEN
The SSOV switch opened during standby.
SSOV FAULT
DURING PURGE
The SSOV switch opened during purge.
SSOV FAULT
DURING IGN
The SSOV switch closed or failed to open during ignition.
SSOV FAULT
DURING RUN
The SSOV switch closed for more than 15 seconds during 
run. 
SSOV RELAY
FAILURE
A failure has been detected in one of the relays that control 
the SSOV. 
STEPPER MOTOR
FAILURE
The Stepper Motor failed to move the Air/Fuel Valve to the 
desired position. 
 
 
