GE Moisture Target Series 6 User Manual page 92

Chapter 4. Service and Maintenance
Table 3: Troubleshooting Guide for Common Problems
Possible Cause
Symptom: The accuracy of the moisture sensor is questioned.
There is insufficient
time for the system to
equilibrate.
Dew point at the
sampling point is
different from the dew
point of the main
stream.
Sensor or sensor
shield is affected by
process contaminants
Sensor is
contaminated with
conductive particles.
Sensor is corroded
Stream particles
causing abrasion.
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Response: Reads too wet during dry down conditions
or too dry in wet up conditions.
Action: Change the flow rate. A change in dew point
indicates the sample system is not at equilibrium or
there is a leak. Allow sufficient time for sample system
to equilibrate and moisture reading to become steady.
Check for leaks.
Response: Reads too wet or too dry.
Action: Readings may be correct if the sampling point
and main stream do not run under the same process
conditions. The different process conditions cause
readings to vary. If sampling point and main stream
conditions are the same, check sample system pipes,
and any pipe between the sample system and main
stream for leaks. Also, check sample system for
adsorbing water surfaces, such as rubber or plastic
tubing, paper-type filters, or condensed water traps.
Remove or replace the contaminating parts with
stainless steel parts.
Response: Reads too wet or too dry
Action: Clean the sensor and the sensor shield, then
reinstall the sensor.
Response: Reads high dew point.
Action: Clean the sensor and the sensor shield, then
reinstall the sensor. Also, install a proper filter (i.e.
sintered or coalescing element).
Response: Reads too wet or too dry
Action: Return probe to factory for evaluation.
Response: Reads too wet or too dry.
Action: Return probe to factory for evaluation.
Moisture Target Series 6 Hygrometer User's Manual
Response and Action