Emerson Process Management IB106-340 instruction manual Fault 8, Low Heater Temp

Oxymitter 4000

	HEATER T/C
DIAGNOSTIC	HEATER	SW2
ALARMS	O2 CELL	ON
	CALIBRATION

CALIBRATION RECOMMENDED

Instruction Manual

IB-106-340 Rev. 2.4

April, 2001

h. Fault 8, Low Heater Temp

The HEATER LED flashes four times,

pauses for three seconds, and repeats

(Figure 7-8).

1. The low heater temperature alarm is

active when the thermocouple reading

TEST

POINTS

INC INC

HIGH LOW

GAS GAS

DEC DEC

O2 CELL mV +

O2 CELL mv - HEATER T/C + HEATER T/C -

CAL

TEST GAS +

PROCESS -

% O2

TP1 TP2 TP3 TP4

TP5 TP6

J1 RED YEL GRN ORG

22220039

has dropped below 28.6 mV.

2. If the thermocouple reading continues

to ramp downward for one minute and

does not return to the temperature set

point of approximately 29.3 mV, then

an Open Heater fault will be displayed.

3. Power down the electronics. Remove

the electronic assembly per paragraph

6-5b,Electronic Assembly Replace-

ment. Using a multimeter, measure

across the heater connector, J8.

Figure 7-8. Fault 8, Low Heater Temp

4. If the heater is good, the reading will be

approximately 70 ohms. If the heater is

open, see paragraph 6-7,Heater Strut

Replacement.

7

Rosemount Analytical Inc. A Division of Emerson Process Management Troubleshooting 7-11