Emerson Rosemount OCX 8800, Instruction Manual

Page: 198 / 306

Instruction Manual
IM-106-880C, OI
Fault Isolation
April 2017
Fault
Isolation
17
1
Slow heatup during cold start Perform Reset procedure in Section 3, Configuration and Startup to
continue operation. If alarm persists, refer to the O2 Htr Failure alarm
procedure.
COe TC Shorted (Combustibles sensor heater thermocouple shorted)
Probable Cause Recommended Corrective Action
Slow heatup during cold start Perform Reset procedure in Section 3, Configuration and Startup to
continue operation. If alarm persists, refer to the COe Htr Failure alarm
procedure.
SB TC Shorted (Sample block heater thermocouple shorted)
Probable Cause Recommended Corrective Action
Slow heatup during cold start Perform Reset procedure in Section 3, Configuration and Startup to
continue operation. If alarm persists, refer to the SB Htr Failure alarm
procedure.
O2 TC Reversed (Oxygen sensor heater thermocouple reversed)
Probable Cause Recommended Corrective Action
SB TC Open (Sample block heater thermocouple open)
Probable Cause
Recommended Corrective Action
O2 TC Shorted (Oxygen sensor heater thermocouple shorted)
Probable Cause
Recommended Corrective Action
COe TC Reversed (Combustibles sensor block heater thermocouple reversed)
Probable Cause
Recommended Corrective Action
SB TC Reversed (Sample block heater thermocouple reversed)
Probable Cause
Recommended Corrective Action
Sample block thermocouple or
thermocouple circuit open Check sample block thermocouple and circuit wires for breaks or loose
connections per
Figure 8-5 and Repair breaks or loose connections or replace
failed thermocouple. Perform Reset procedure in Section 3, Configuration and
Startup to continue operation.
O
2
thermocouple or thermocouple circuit
shorted
Check O
2
thermocouple and circuit wires for short circuit condition per Figure
8-5 and . Repair shorted wiring or replace failed thermocouple. Perform Reset
procedure in Section 3, Configuration and Startup to continue operation.
Combustibles sensor thermocouple
shorted Check thermocouple resistance (lead to ground) of reference and active
thermocouples per
Figure 8-5 and . If either thermocouple is open or shorted to
ground, replace combustibles sensor.
Sample block thermocouple or
thermocouple circuit shorted Check sample block thermocouple and circuit wires for short circuit condition
per
Figure 8-5 and . Repair shorted wiring or replace failed thermocouple.
Perform Reset procedure in Section 3, Configuration and Startup to
continue operation.
O
2
thermocouple wires reversed Check O
2
thermocouple wiring per Figure 8-5 and . Check the wiring at the
sensor and inside the electronics housing. Correct reversed-wires fault. Perform
Reset procedure in Section 3, Configuration and Startup to continue operation.
Combustibles thermocouple wires reversed Check combustibles thermocouple wiring per Figure 8-5 and . Check the wiring
at the sensor and inside the electronics housing. Correct reversed-wires fault.
Perform Reset procedure in
Section 3, Configuration and Startup to
continue operation.
Sample block thermocouple wires reversed Check sample block thermocouple wiring per Figure 8-5 and . Check the wiring
at the sensor and inside the electronics housing. Correct reversed-wires fault.
Perform Reset procedure in
Section 3, Configuration and Startup to
continue operation.
Table continued on next page