Emerson OCX 8800 instruction manual SB TC Open Sample block heater thermocouple open

Instruction Manual

IM-106-880, Rev 1.0

January 2007

SB TC Open (Sample block heater thermocouple open)

OCX 8800

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 8-3 and Figure 7-4. 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

O2 thermocouple or thermocouple circuit shorted	Check O2 thermocouple and circuit wires for short circuit condition per Figure 8-3 and
	Figure 7-4. Repair shorted wiring or replace failed thermocouple. Perform Reset
	procedure in Section 3, Configuration and Startup to continue operation.
	Perform Reset procedure in Section 3, Configuration and Startup to continue operation.
Slow heatup during cold start
	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 8-3 and Figure 7-5. If either thermocouple is open or shorted to ground,
	replace combustibles sensor.
	Perform Reset procedure in Section 3, Configuration and Startup to continue operation.
Slow heatup during cold start
	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 8-3 and Figure 7-4. 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

O2 thermocouple wires reversed	Check O2 thermocouple wiring per Figure 8-3 and Figure 7-4. 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 8-3 and Figure 7-5. 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 8-3 and Figure 7-4. 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

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