Thermo Scientific FOCUS GC, Instruction Manual

Page: 298 / 356

Chapter 15
Maintenance and Troubleshooting
Maintaining a TCD
298 Instruction Manual
Maintaining a TCD
The TCD detector does not usually need current maintenance. Nevertheless, if
you follow a few simple sequences, you will prolong the detector’s lifetime. Pay a
special attention to avoid contamination or damage of the filaments.
Follow these simple rules:
• Avoid to activate/deactivate the bridge when not necessary. This operation
could considerably reduce the filaments lifetime.
• Avoid injecting samples that contain halogenated or acid compounds at high
concentrations.
• Ensure that oxygen (air) could not enter into the filaments cells. Oxidation
would irreversibly damage the filaments. Install traps for moisture and oxy-
gen on the gas lines to reduce the hazard.
WARNING! Set
Filament power
to
Off
before disconnecting the column from the detector.
When the column is disconnected, air will enter into the cell and the filament, if
powered, will burn.
For the same reason set
Filament power
to
On
only if the column has been
connected. It is a good practice to let the reference and make-up gases flow through
the cells for 10-15 minutes before powering the filaments.
Figure 15-21 shows the Thermal Conductivity Detector components.