MSA Chemgard - Page 55

Section 5, Maintenance
Chemgard Infrared Gas Monitor
5-2
Table 5-2. Troubleshooting Guidelines
TROUBLE
DESCRIPTION
SOLUTION
Unit will not turn ON No power
1. Check AC power to unit.
2. Verify AC power to unit is wired properly.
3. Replace L1 and/or L2 fuse.
4. Check for loose wires on terminal barrier input.
5. Check wiring to the unit power supply.
Remove power supply cover and check fuse; replace if necessary.
6. Check input cable to main board on left side of power supply.
7. Check for 12 VDC power supply output.
Connect the DVM negative lead to TP5 and the positive lead to TPSPD1.
Adjust Volt 2 pot on the power supply if necessary.
8. Move the DVM positive lead to TPSPD3. The voltage should be 5 VDC.
Adjust Volt 1 pot on power supply if necessary.
Beacon will not light Beacon alarm
1. Check that plug is connected to circuit board: J10
2. Verify the audio option is used in the setup screens.
3. Replace beacon assembly.
Under-range failed
Zero limit is
minus 10
ppm
1. Adjust display zero to 0.0 via the keypad with zero air or zero scrubber applied.
2. Check the zero air cylinder; replace if necessary.
3. Check the zero scrubber; replace if necessary.
Calibration failed
Coefficients
out of range
1. Replace zero scrubber or change zero air supply.
2. Check span gas supply.
3. Check all tubing, filters and fittings for leaks.
4. For sequencer units, make sure the unit is locked on the selected sample port used for
calibration.
5. Leak test the flow system.
6. Return to MSA for service.
Bypass flow failed
Leaky or
blocked
bypass line
1. Remove all input lines to unit.
Attach one line at a time to check for bypass input. The line that causes flow failure is
the problem; check the line’s end-of-line filter.
2. Check inlet fitting, tubing, orifices, bypass pressure switch, and bypass manifold tubing.
3. Check pressure switch for 4 VDC ON and OFF switching (if sequencing);
if single-point, it will be ON constantly.
Check cable terminals and plug end at BP/SCN. Replace the bypass pressure switch if
necessary.
4. Check operation of all bypass valves in manifold.
5. Leak test the flow system.