Emerson ROSEMOUNT OCX 8800 - Manual (Page 103)

Instruction Manual
IM-106-880, Rev 1.0
January 2007
7-5
OCX 8800
SB TC Open (Sample block heater thermocouple open)
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 7-3 and Figure 6-6. Repair breaks or loose connections or replace failed
thermocouple. Perform Reset procedure in Section 3, Configuration and Startup to
continue operation.
O2 TC Shorted (Oxygen sensor heater thermocouple shorted)
Probable Cause Recommended Corrective Action
O
2
thermocouple or thermocouple circuit shorted Check O
2
thermocouple and circuit wires for short circuit condition per Figure 7-3 and
Figure 6-6. Repair shorted wiring or replace failed thermocouple. Perform Reset
procedure in Section 3, Configuration and Startup to continue operation.
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
Combustibles sensor thermocouple shorted Check thermocouple resistance (lead to ground) of reference and active thermocouples
per Figure 7-3 and Figure 6-7. If either thermocouple is open or shorted to ground,
replace combustibles sensor.
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
Sample block thermocouple or thermocouple
circuit shorted Check sample block thermocouple and circuit wires for short circuit condition per
Figure 7-3 and Figure 6-6. Repair shorted wiring or replace failed thermocouple.
Perform Reset procedure in Section 3, Configuration and Startup to continue operation.
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
O
2
thermocouple wires reversed Check O
2
thermocouple wiring per Figure 7-3 and Figure 6-6. 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.
COe TC Reversed (Combustibles sensor block heater thermocouple reversed)
Probable Cause Recommended Corrective Action
Combustibles thermocouple wires reversed Check combustibles thermocouple wiring per Figure 7-3 and Figure 6-7. 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.
SB TC Reversed (Sample block heater thermocouple reversed)
Probable Cause Recommended Corrective Action
Sample block thermocouple wires reversed Check sample block thermocouple wiring per Figure 7-3 and Figure 6-6. 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