Common Problems - GE Moisture Image 1 Series Service Manual

June 2003

Common Problems

Table 2-5: Troubleshooting Guide for Common Problems
Symptom Possible Cause
Accuracy of mois- Insufficient time for sys-
ture sensor is tem to equilibrate
questioned.
Dew point at sampling
point is different than the
dew point of the main
stream.
Sensor or sensor shield
affected by process con-
taminants (refer to Appen-
dix A).
Sensor is contaminated
with conductive particles
(refer to Appendix A).
Sensor is corroded (refer
to Appendix A).
Sensor temperature is
greater than 70°C
(158°F).
Stream particles causing
abrasion.
2-12
If the Series 1 measurement readings seem strange, or they do not
make sense, there may be a problem with the probe or a component of
the process system. Table 2-5 contains some of the most common
measurement 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 sample system to
equilibrate and 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. The differ-
ent process conditions cause readings to
vary. Refer to Chapter 1 of the Startup
Guide for more information. 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 sam-
ple 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 Aluminum Oxide Probe
Maintenance on page A-7 in Appendix
A. Then reinstall sensor.
Clean the sensor and the sensor shield as
described in Aluminum Oxide Probe
Maintenance on page A-7 in Appendix
A. Then reinstall sensor.
Return probe to factory for evaluation.
Return probe to factory for evaluation.
Return probe to factory for evaluation.
Troubleshooting and Maintenance