Emerson Process Management OXYMITTER 4000 Alarms O2 Heater Open, Fault 5, Open Heater

Hazardous Area Oxymitter 4000

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

CALIBRATION RECOMMENDED

Instruction Manual

IB-106-340C Rev. 4.1

July 2004

e. Fault 5, Open Heater

Figure 8-7shows the electronic assembly

for a Hazardous Area Oxymitter 4000 with

a membrane keypad (upper view) and a

Hazardous Area Oxymitter 4000 with an

LOI (lower view).

Membrane Keypad. When Fault 5 is

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

detected, the HEATER LED flashes once,
pauses for three seconds, and repeats.
1.	Remove power.
2.	Remove the electronic assembly per
	paragraph 9-4c,Electronic Assembly
	Replacement.
3.	Using a multimeter, measure the re-
	sistance across the terminals of heater
	connector, J8.

KEYPAD

Alarms

O2 Heater Open

LOI 37260023

Figure 8-7. Fault 5, Open Heater

4. The measurement should be approxi-

mately 72 ohms. If the heater is open,

see paragraph 9-4g,Heater Strut

Replacement.

LOI. When Fault 5 is detected, the LOI dis- plays the “O2 Heater Open” message.

1.Remove power. Unscrew and remove the LOI module from the electronic as- sembly.

2.Perform the diagnostic steps 2 through 4 shown for the membrane keypad.

8

Rosemount Analytical Inc. A Division of Emerson Process Management Troubleshooting 8-9