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Discrepancy between analog output and display, Other performance problems, Excessive noise – Teledyne 6200E - Sulfides Analyzer User Manual

Page 250: Slow response

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TROUBLESHOOTING & REPAIR

Model 6200E Instruction Manual

250

M6200E Rev: A1

• Sample inlet may be contaminated with H

2

S exhaust from this or other analyzers. Verify

proper venting of the pump 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. Make sure to create and properly vent excess
span gas.

• If the instrument is equipped with an intern IZS valve option and the H

2

S span value is

continuously trending downward, the IZS permeation tube may require replacement

11.3.7. 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. See Section 6.9.4.3. for a detailed description of this

procedure.

11.4. Other Performance Problems

Dynamic problems (i.e. problems which only manifest themselves when the analyzer is monitoring
sample gas) can be the most difficult and time consuming to isolate and resolve. The following
section provides an itemized list of the most common dynamic problems with recommended
troubleshooting checks and corrective actions.

11.4.1. Excessive noise

Excessive noise levels under normal operation usually indicate leaks in the sample supply or the

analyzer itself. Make sure that the sample or span gas supply is leak-free and carry out a detailed
leak check as described earlier in this chapter.

Another possibility of excessive signal noise may be the preamplifier board, the high voltage
power supply and/or the PMT detector itself. Contact the factory on trouble-shooting these

components.

11.4.2. Slow Response

If the analyzer starts responding too slowly to any changes in sample, zero or span gas, check for

the following:

• Dirty or plugged sample filter or sample lines.

• Sample inlet line is too long.

• Dirty or plugged critical flow orifices. Check flows (Section 11.5.2), pressures (Section

11.5.1) and, if necessary, change the critical flow orifice (Section 9.3.7).

• Wrong materials in contact with sample - use Teflon materials only.

• Sample vent line is located too far from the instrument sample inlet and causes long

mixing and purge times. Locate sample inlet (overflow) vent as close as possible to the
analyzer’s sample inlet port.