Teledyne T100, Instruction Manual, Page: 271 / 404

Teledyne ML - T100 UV Fluorescence SO2 Analyzer Troubleshooting & Repair
06807A(DCNxxxx) 271
10.4.5. INABILITY TO ZERO - NO ZERO BUTTON
In general, the T100 will not display certain control buttons whenever the actual value of
a parameter is outside of the expected range for that parameter. If the calibration menu
does not show a ZERO button when carrying out a zero calibration, the actual gas
concentration must be significantly different from the actual zero point (as per last
calibration), which can have several reasons.

Confirm that there is a good source of zero air. If the IZS option is installed, compare the zero
reading from the IZS zero air source to an external zero air source using SO
2
-free air. Check
any zero air scrubber for performance and replacement (refer to Section 8.3.3).

Check to ensure that there is no ambient air leaking into the zero air line. Check for leaks in
the pneumatic systems as described in Section 8.3.6.
10.4.6. NON-LINEAR RESPONSE
The T100 was factory calibrated and should be linear to within 1% of full scale. Common
causes for non-linearity are:

Leaks in the pneumatic system. Leaks can add a constant of ambient air, zero air or span gas
to the current sample gas stream, which may be changing in concentrations as the linearity
test is performed. Check for leaks as described in Section 10.6.

The calibration device is in error. Check flow rates and concentrations, particularly when
using low concentrations. If a mass flow calibrator is used and the flow is less than 10% of
the full scale flow on either flow controller, you may need to purchase lower concentration
standards.

The standard gases may be mislabeled as to type or concentration. Labeled concentrations
may be outside the certified tolerance.

The sample delivery system may be contaminated. Check for dirt in the sample lines or
sample chamber.

Calibration gas source may be contaminated.

Dilution air contains sample or span gas.

Sample inlet may be contaminated with SO
2
exhaust from this or other analyzers. Verify
proper venting of the analyzer’s exhaust.

Span gas overflow is not properly vented and creates a back-pressure on the sample inlet port.
Also, if the span gas is not vented at all and does not supply enough sample gas, the analyzer
may be evacuating the sample line. Ensure to create and properly vent excess span gas.

If the instrument is equipped with an internal IZS valve option and the SO
2
span value is
continuously trending downward, the IZS permeation tube may require replacement.
10.4.7. DISCREPANCY BETWEEN ANALOG OUTPUT AND DISPLAY
If the concentration reported through the analog outputs does not agree with the value
reported on the front panel, you may need to re-calibrate the analog outputs. This
becomes more likely when using a low concentration or low analog output range. Analog
outputs running at 0.1 V full scale should always be calibrated manually. Refer to Section
4.8.4.3 for a detailed description of this procedure.