GE Moisture Image 1 Series, Руководство по обслуживанию, Страница: 44 / 107

June 2003
2-12 Troubleshooting and Maintenance
Common Problems
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.
.
Table 2-5: Troubleshooting Guide for Common Problems
Symptom Possible Cause System Response Action
Accuracy of mois-
ture sensor is
questioned. Insufficient time for sys-
tem to equilibrate
Dew point at sampling
point is different than the
dew point of the main
stream.
Probe reads too wet during dry
down conditions, or too dry in
wet up conditions.
Probe reads too wet or too dry.
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.
Sensor or sensor shield
affected by process con-
taminants (refer to Appen-
dix A). Probe reads too wet or too dry. Clean the sensor and the sensor shield as
described in
Aluminum Oxide Probe
Maintenance on page A-7 in Appendix
A. Then reinstall sensor.
Sensor is contaminated
with conductive particles
(refer to Appendix A). Probe reads high dew point. Clean the sensor and the sensor shield as
described in
Aluminum Oxide Probe
Maintenance on page A-7 in Appendix
A. Then reinstall sensor.
Sensor is corroded (refer
to Appendix A). Probe reads too wet or too dry. Return probe to factory for evaluation.
Sensor temperature is
greater than 70°C
(158°F). Probe reads too dry. Return probe to factory for evaluation.
Stream particles causing
abrasion. Probe reads too wet or too dry Return probe to factory for evaluation.