112 Maintenance and Service 083730300A DCN8101
soap solution, do not re-apply vacuum, as it will suck soap solution into the
instrument and contaminate it. Do not exceed 15 psi pressure.
5. If the instrument has one of the zero and span valve options, the normally closed
ports on each valve should also be separately checked. Connect the leak checker
to the normally closed ports and check with soap bubble solution.
6. Once the leak has been located and repaired, the leak-down rate should be < 1 in-
Hg (0.4 psi) in 5 minutes after the pressure is shut off.
5.6.4 PERFORMING A SAMPLE FLOW CHECK
General Safety Hazard
Always use a separate calibrated flow meter capable of measuring
flows in the 0 – 1000 cm
3
/min range to measure the gas flow rate
though the analyzer.
DO NOT use the built in flow measurement viewable from the Front
Panel of the instrument. This measurement is only for detecting
major flow interruptions such as clogged or plugged gas lines.
See Figure 2-2 for SAMPLE port location.
1. Attach the Flow Meter to the sample inlet port on the rear panel. Ensure that the
inlet to the Flow Meter is at atmospheric pressure.
2. Sample flow should be 800 cm
3
/min ± 10%.
3. Once an accurate measurement has been recorded by the method described
above, adjust the analyzer’s internal flow sensors (See Section 4.5.3).
Low flows indicate blockage somewhere in the pneumatic pathway, typically a plugged
sintered filter or critical flow orifice in one of the analyzer’s flow control assemblies.
High flows indicate leaks downstream of the Flow Control Assembly.
5.6.5 CLEANING THE OPTICAL BENCH
The T300/T300M sensor assembly and optical bench are complex and delicate.
Disassembly and cleaning is not recommended. Please check with the factory before
disassembling the optical bench.
5.7 SERVICE AND TROUBLESHOOTING
This contains a variety of methods for identifying the source of performance problems
with the analyzer. Also included in this are procedures that are used in repairing the
instrument.
Qualified Personnel
The operations outlined in this Section must be performed by qualified
maintenance personnel only.
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