Thermo Scientific FOCUS GC, Instruction Manual, Page: 76 / 356

Chapter 3
Gas Control
Detector Gas Regulation
76 Instruction Manual
FID Gases
The FID requires hydrogen and air as fuel gas and nitrogen as make-up gas.
The adjustment of the detector gases flow is done in factory prior shipment.
Verify that the corresponding gases flows are correct. If not, adjust the value
turning the relevant regulation screw as shown in Figure 3-1.
Figure 3-1. FID-External Detector Gases Flow Regulation.
The flow is measured at the exit of the detector base body. Enter the FID detector
control menu to turn the flow on/off.
TCD Gases
The TCD detector requires the same gas whether for the measure channel (carrier
and make-up gas, when necessary) and the reference channel (reference gas)
Helium is the recommended carrier gas due to its high thermal conductivity and
chemical inertness.
The adjustment of the detector gases flow is done in factory prior shipment.
Gas Flow
Hydrogen (fuel gas) 35 mL/min
Air (fuel gas) 350 mL/min
Nitrogen (make-up gas) 30 mL/min
1 turn clockwise of the regulation screw increases the flow of about 2.5 mL/min
1 turn counterclockwise of the regulation screw decreases the flow of about 2.5 mL/min
OPEN
H2 Air
FID - External Detector
Make-up
OPEN