Model NGA 2000 TO2
Instruction Manual
SECTION 5
TROUBLESHOOTING
5-1 TROUBLESHOOTING
The following provides a short list of common troubleshooting tips. Additional information is contained in the Platform Manual.
a.Failure to purge down to ppm levels
Prior to conducting any changes to the system, try running a quick start se- quence (see section 3.4) to see if the oxygen reading goes lower. If the reading does decrease, the sensor has not been allowed sufficient time to consume the dissolved oxygen in the electrolyte. If the reading continues to read high a leak may exist in the sample lines. The number one problem associated with trace oxygen analyzer installation is the occurrence of leaks in your sample plumbing. If the oxygen reading will not come down to ppm levels or is reading higher than ex- pected, the sample plumbing prior to the instrument may have a leak. A quick check can be conducted by observing the oxygen reading at two different flow lev- els; 0.5 and 2.0 scfh. If the oxygen read- ing drops significantly when the flow is increased from 0.5 to 2.0 scfh, this is a good indication that a leak exists.
To check for leaks prior to the sensor, disconnect the Analyzer Module and cap the inlet line. Pressurize the inlet line to 5 - 10 psig and check all connections with a soapy solution (SNOOP®) to identify leaks.
WARNING.
SENSOR DAMAGE
Do not pressure check the sample line with the sensor connected. Over- pressurization of the sensor can result in damage.
b.Flow sensitivity
Check to make sure that your vent line is not blocked. If you see a rise in reading with an increase in flow, you may be over- pressurizing the sensor due to a blocked vent. Since the sensor is a partial pres- sure measuring device, an increase in sample pressure will cause an increase in reading. If the reading drops with in- creased flow, conduct the leak check out- lined in the troubleshooting tip above.
c.Erratic and very insensitive readings
Check to see that the electrolyte level is within the limits indicated on the reservoir. Add distilled water as required. If the level is within limits, the electrolyte may have been contaminated. Refer to sec- tion 4.2 above for proper procedure to re- place electrolyte. If replacement of electrolyte does not improve the perform- ance of the sensor, the sensor may have been damaged due to
Rosemount Analytical Inc. A Division of Emerson Process Management | Troubleshooting |
