Teledyne 6400EH - Sulfur Dioxide Analyzer - Manual (Page 56)

Troubleshooting Model 6400EH
Teledyne Analytical Instruments 44
If you suspect that one of the two pressure sensors is failing:
1. Cap the sample inlet.
2. After a few seconds, check the
VAC and PRES test functions and
verify that:
 The
VAC value matches the PRES value to within 1 In-Hg-A,
and;
 Both are less than 10 in-Hg-A (i.e. under vacuum).
3. Uncap the sample inlet and unplug the pump.
4. After a few minutes, the value
VAC and PRES should match
within 1 In-Hg-A, and read atmospheric pressure.
 If the two sensors do not match or are significantly different from
ambient atmospheric pressure, call Teledyne Analytical Instruments
customer service.
10.3 Repair Procedures
10.3.1 Repairing the Sample Gas Flow Control Assembly
The Critical Flow Orifice is part of the pressure sensor and flow
control assembly. The jewel orifice is protected by a sintered filter, so it
is unusual for the orifice to need replacing, but it is possible for the
sintered filter and o-rings to need replacing. See the Spare Parts list in
Appendix B for part numbers and kits.
To replace the filter and/or orifice
1. Turn off Power to the analyzer.
2. Locate the pressure sensor / flow control assembly.
3. Disconnect the signal cable and pneumatic fittings.
4. Remove the assembly from the optical bench by removing the 2
screws at each end of the assembly.
5. The inlet end of the assembly is located at the end with the
straight pneumatic fitting. Remove the fitting and the
components as shown in the exploded view.
6. Replace the o-rings (p/n:OR01) and the sintered filter (p/n:
FL01).