Detcon PI-700 - Manual (Page 43)

Model PI-700
PI-700 Instruction Manual Rev. 2.5 Page 39 of 54
6. Troubleshooting Guide
Refer to the list of Failsafe Diagnostic features listed in Section 3.6.2 for additional reference in
troubleshooting activities. Listed below are some typical trouble conditions and their probable cause and
resolution path.
Figure 32 Sensor Cell and ITM Mating
Under-Range Fault
Probable Cause: Sensor Baseline drifted lower, Ambient Interference gasses reduced.
 Repeat AutoZero. Use Zero Air or N
2
source.
 Execute successful AutoSpan and verify adequate Sensor Life.
 Check Raw counts in View Sensor Status. Count should be close to 1,500 for high range and 3,000
for low range.
 Replace plug-in sensor if fault continues.
Missing Sensor Fault
Probable Cause: Sensor is Missing, Failed Plug-in Sensor Electronics, or ITM I.S. Barrier Failure.
 Make sure plug-in sensor is plugged in properly with correct orientation.
 Swap plug-in sensor into another ITM to determine if plug-in sensor problem or ITM problem.
 Replace the plug-in sensor if proven faulty.
 Replace the ITM if proven faulty.
AutoSpan Calibration Faults – (Range, Stability and Clearing)
To clear any AutoSpan Calibration fault, the AutoSpan process must be completed successfully (Section 3.4).
Use zero air gas after AutoSpan Calibration to avoid clearing fault from high background VOC levels.
Range Fault
Probable Causes: Failed Sensor, Cal Gas not applied or not applied at appropriate time, or problems w/ cal gas
and delivery.
 Check validity of span gas (check MFG date on cal gas cylinder).
 Use proper cal gas regulators and tubing for highly absorbing or corrosive gasses.
 If using Splashguard with Integral Cal Port, must use Calibration Wind Guard or air movement can
compromise span gas delivery.
 Check for obstructions affecting cal gas hitting sensor face (including being wet, blocked, or
corroded).
Plug-in Sensor
(Bottom View)
ITM
Bottom View
Locking Setscrew
Display Window