Common Problems - GE moisture.iq User Manual

Chapter 8. Troubleshooting

8.2 Common Problems

If the moisture.IQ measurement readings seem strange or do not make sense, there may be a problem with the
probe or the process system. Table 12 below contains some of the most common measurement problems.
Symptom Possible Cause
Accuracy of Insufficient time for
moisture system to equilibrate
sensor is
questioned.
Dew point at sampling
point is different than the
dew point of the main
stream.
Sensor or sensor shield
affected by process
contaminants (refer to
Basic Hygrometry
Principles).
Sensor is contaminated
with conductive particles
(refer to Basic Hygrometry
Principles).
Sensor is corroded (refer to
Basic Hygrometry
Principles).
Sensor temperature is
greater than 70°C (158°F).
Stream particles are
causing abrasion.
96
Table 12: Troubleshooting Guide for Common Problems
System Response
Probe reads too wet
during dry down
conditions, or too dry
in wet up conditions.
Probe reads too wet or
too dry.
Probe reads too wet or
too dry.
Probe reads high dew
point.
Probe reads too wet or
too dry.
Probe reads too dry.
Probe reads too wet or
too dry
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 the sample system to equilibrate and
the moisture reading to become steady. Check
for leaks.
Readings may be correct if the sampling point
and main stream do not run under the same
process conditions. 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 contaminating
parts with stainless steel parts.
Clean the sensor and the sensor shield as
described in document 916-064, Basic
Hygrometry Principles. Then reinstall sensor.
Clean the sensor and the sensor shield as
described in document 916-064, Basic
Hygrometry Principles. Then reinstall sensor.
Return probe to factory for evaluation.
Return probe to factory for evaluation.
Return probe to factory for evaluation.
moisture.IQ User's Manual