Replacing An Is-Tcd Dpm - Siemens Maxum II Service Manual

4. Remove the Thermistor/Filament Board (12) by removing the Button Head Hex Screw (9),
the Lockwasher (10), and the Flat Washer (11).
5. Discard board (12) and O-rings (13). Do not attempt to reuse old O-rings.
6. Remove the two metal inserts (14). These CAN be reused.
7. Before installing new board, examine the mounting surface and the holes for the Filaments/
Thermistors to verify there is no contamination or scratches on the machined surface.
If there is contamination on the surface, clean it using a lint free cloth and a cleaning solvent
such as acetone or hexane. If the surface is scratched it may be necessary to replace the
complete assembly.
Note
The elements on the board are exposed and are very delicate. Handle the board only by
its edges.
Hands and tools must be clean.
8. Install the metal inserts (14) in the detector block (4). These inserts should be installed with
the groove perpendicular to the tube holes in the block (so that air cannot flow in a straight
path between the holes). Refer to Figure 6-10.
9. Install the new O-rings (13) in hole in the Detector Block (4).
It is also possible to install the O-rings on the Thermistor / Filament board (12) instead of
in the hole. If installing the O-rings on the board, be careful not to damage the element.
10.Install the Board (12) into the Detector Block (4). When installing the board, exercise caution
not to damage the exposed elements.
11.Reinstall the Flat Washer (11), Lock Washer (10), and Button Head Hex Screw (9). Do not
over tighten the screw as this can damage the Board (12).
12.Reconnect wiring (8) to the board (12). Wiring MUST be connected to the same cells as
before. Verify all termination points.
Note: The color coding information for the wiring should be on the Detector Certification
Label (1). Also note that there are two wires of each color. For a specific cell it does not
matter which wire is connected to which lead as long as the color is correct.
13.Before installing cover back on the Detector Block (4), turn on carrier air to verify there are
no leaks between the Board (12) and the Block (4). Turn off carrier after this check is
complete.
14.Set the cover in place and reinstall the 4 screws and lockwashers (3) that secure the cover
to the detector block (4).
2.2.3

Replacing an IS-TCD DPM

Note
While the IS TCD DPMs are similar, the detector connectors are not compatible.
● The IS TCD4 DPM CAN be used as a replacement for the IS TCD3 DPM with an adapter.
● The IS TCD3 DPM CANNOT be used as a replacement for the IS TCD4 DPM.
Maxum Edition II Detectors
Service Manual, May 2018, A5E42019847001
Thermal Conductivity Detector
2.2 Replacing TCD Components
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