Emerson Rosemount OCX8800 Instruction Manual page 197

Fault Isolation
April 2017
SB Temp Hi (Sample block heater temperature high, > 190 ºC)
Probable Cause
High noise in OCX power supply
O2 Temp Very Hi (Oxygen sensor heater over maximum temperature, > 820 ºC)
O2 Htr Rmp Rate (Oxygen sensor heater over maximum temperature ramp rate)
Probable Cause
Incorrect O heater wiring
2
Incorrect O thermocouple wiring
2
Electronics package failure
COe Temp Very Hi (Combustion sensor heater over maximum temperature, > 400 ºC)
COe Htr Rmp Rate (Combustibles sensor heater over maximum temperature ramp rate)
Probable Cause
Incorrect COe heater wiring
Incorrect COe thermocouple wiring
Electronics package failure
SB Temp Very Hi (Sample block heater over maximum temperature, > 260 ºC)
SB Htr Rmp Rate (Sample block heater over maximum temperature ramp rate)
Probable Cause
Incorrect sample block heater wiring
Incorrect sample block thermocouple
wiring
Electronics package failure
O2 TC Open (Oxygen sensor heater thermocouple open)
Probable Cause
O thermocouple or thermocouple circuit
2
open
COe TC Open (Combustibles sensor heater thermocouple open)
Probable Cause
Combustibles sensor thermocouple open
Table continued on next page
17
0
Recommended Corrective Action
Check power supply for line noise or voltage fluctuations. Install power line filter
kit
(PN 6A00171G01) or high quality line filter for input power.
Recommended Corrective Action
Check O heater wiring per
2
inside the electronics housing. Correct wiring fault. Perform Reset procedure in
Section 3, Configuration and Startup to continue operation.
Check O thermocouple wiring per
2
thermocouple and inside the electronics housing. Correct wiring fault. Perform
Reset procedure in Section 3, Configuration and Startup to continue operation.
Replace electronics package.
Recommended Corrective Action
Check COe heater wiring per
inside the electronics housing. Correct wiring fault. Perform Reset procedure in
Section 3, Configuration and Startup
Check COe thermocouple wiring per
thermocouple and inside the electronics housing. Correct wiring fault. Perform
Reset procedure in Section 3, Configuration and Startup
operation.
Replace electronics package.
Recommended Corrective Action
Check sample block heater wiring per
wiring at the heater and inside the electronics housing. Correct wiring fault.
Perform Reset procedure in Section 3, Configuration and Startup to continue
operation.
Check sample block thermocouple wiring per
the wiring at the thermocouple and inside the electronics housing. Correct
wiring fault. Perform Reset procedure in Section 3, Configuration and Startup to
continue operation.
Replace electronics package.
Recommended Corrective Action
Check O thermocouple and circuit wires for breaks or loose connections per
2
Figure 8-5 and . Repair breaks or loose connections or replace failed
thermocouple. Perform Reset procedure in
Startup to continue operation.
Recommended Corrective Action
Check thermocouple resistance (lead to ground) of reference and active
thermocouples per Figure 8-5
ground, replace combustibles sensor.
Figure 8-5 and . Check the wiring at the heater and
Figure 8-5 and . Check the wiring at the
Figure 8-5 and . Check the wiring at the heater and
to continue operation.
Figure 8-5 and . Check the wiring at the
Figure 8-5 and Figure
Figure 8-5
Section 3, Configuration and
and . If either thermocouple is open or shorted to
Instruction Manual
IM-106-880C, OI
to continue
9-9. Check the
and Figure 9-9. Check
Fault
Isolation