Detcon 1000_H2S - Manual (Page 27)

Model 1000 H2S Echem
Model 1000 H2S Echem Instruction Manual Rev. 2.8 Page 23 of 30
12. Sensor Replacement
Should the electrochemical H
2
S plug-in sensor (part number 370-323200-000 or 370-3H3H00-000) require
replacement, use the following procedure:
1 - (A) If the sensor is mounted in a classified area, system power to the transmitter must first be removed
before proceeding further.
(B) If in an unclassified area, remove front enclosure cover and unplug transmitter module.
2 - Remove gas flow adapter and tubing connections to expose sensor housing.
3 - Unscrew the three screws of the sensor head bottom.
4 - Pull the sensor head bottom down and off.
5 - Grasp the electrochemical sensor cell and unplug by pulling down.
6 - Plug in the new sensor. Replace the sensor head bottom and screw in place.
7 - Re-attach gas inlet adapter and tubing connections.
8 - Restore system power (if classified) or plug in transmitter module and replace enclosure cover (if
unclassified).
9 - Perform a new zero and span calibration after 1-2 hours of warm-up time.
13. Troubleshooting
Reading higher or lower than anticipated
Probable cause: Incorrect sample flow or air flow, degraded cal gas, or needs to be zero and span calibrated.
1. Check for correct sample flow “S
 ” marking 200cc/min.
2. Check for correct air flow “
” marking 500cc/min.
3. Check span gas is same as programmed AutoSpan value.
4. Check Span Calibration gas for valid concentration in nitrogen gas using H
2
S pull tube.
5. Re-calibrate sensors with known good span gas.
6. Re-zero sensor per instruction manual.
“Span Fault” Error
1. Check for correct calibration gas flow “C
” marking, 250cc/min.
2. Check for correct air flow “
” marking, 500cc/min.
3. Check Span Calibration gas for valid concentration in nitrogen gas using H
2
S pull tube.
4. Re-calibrate with known good span gas.
5. Consider electrochemical sensor replacement if reported Sensor Life is <50%.
Slow sensor response during Span Calibration
Probable cause: Incorrect sample flow or airflow, or bad span gas, or slow response sensor.
1. Check for correct calibration gas flow “C
” marking, 250cc/min.
2. Check for correct air flow “
” marking, 500cc/min.
3. Check Span Calibration gas for valid concentration in nitrogen gas.
4. Re-calibrate with known good span gas.
5. If problem persists, the sensor may need to be replaced. Contact factory.
Sample gas and/or air flow reduced, Flow Fault lights activated (optional)
Probable cause: Incorrect sample gas inlet pressure or the sample gas or airflow has been obstructed by,
blocked Genie membrane filter, failed air pump, vent lines blocked, rotameters accidentally turned down.
1. Check for liquid in the sample flow inlet line.
2. Check for adequate sample gas inlet pressure (10 ±2psig).
3. Check for obstruction in the air-inlet pump.
4. Open the Sample by-pass liquid rejection port to release any liquid trapped in the Genie Membrane filter.
Leave sample by-pass open to allow ~100-200cc/min of gas out.
5. Replace Genie membrane if permanently blocked.