Table 2-2. Gas Analyzer Troubleshooting

TM 5-6640-212-14

Table 2-2.

Gas Analyzer Troubleshooting

MALFUNCTION

TEST OR INSPECTION

CORRECTIVE ACTION

NOT POSSIBLE TO MAKE ZERO ADJUSTMENT WITHIN SPAN OF ZERO ADJUSTER IN ABSENCE

OF COMBUSTIBLE GAS.

Step 1. Check by substitution of another detector unit.

a. If zero adjustment is within range of zero adjuster replace old detector unit.

b. Check detector voltage between the detector voltage test (on P.C. board).

c. Insure module is fully inserted into its socket.

Step 2. Voltage still incorrect after element replacement.

Replace P.C. board.

NO POWER TO GAS ANALYZER (ALL LIGHTS OFF).

Check fuse on circuit breaker.

a. Replace fuse or reset circuit breaker.

b. Check other equipment for availability of power, if no power check source and correct.

FAIL LIGHT IS ON.

If equipment failure occurs, the fail light will come on, external failure terminal will switch, and alarm circuits will

disable to prevent false alarms.

a. Check if detector voltage set abnormally low. Adjust as necessary.

b. Check for excessive negative meter drift. Adjust as necessary.

c. Check for a short or open circuit in the detector circuit. Repair or replace as necessary.

METER CANNOT BE SET TO ZERO WITH TWO DETECTORS ON LINE.

Check if one detector is installed and the other detector removed from the control module, and a set of 15-ohm

resistors set across the DET 2A-C-R terminals. If detector or resistors are missing proper zero setting cannot

be done.

If zero cannot be set, there is a mismatch between the two sensors; replace the older

sensor with a new one, and adjust potentiometer R24 for a zero adjustment.

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