Bacharach HI FLOW Sampler, Instruction, Page: 58 / 72

Maintenance Hi Flow Sampler
Instruction 0055-9017
54
5.5 Gas Sensor Replacement
Replace a gas sensor when it fails to calibrate per Section 4 Calibration .
The gas sensors are located inside their associated flow blocks of the
leak-gas and background-gas sensor assemblies. See Figure 5-5.
Figure 5-5. Leak-Gas & Background Gas Sensor Assemblies
Equipment Required:

Medium Phillips Head Screwdriver

Replacement Sensor (P/N 0055-0040)
Procedure:
1.
Remove cover per Section 5.3.
2. Remove the pump connector and multi-pin connector from printed
circuit board, noting orientation of connectors. See Figure 5-6.
3. Remove three screws from printed circuit board; then carefully pry
the board straight up from the flow block. The gas sensor is the silver
cylindrical piece in the center of the circuit board.
4. Pull sensor from circuit board and replace with a new sensor, making
sure that the new sensor is firmly seated into its receptacles and
bottomed on circuit board.
5. Reinstall printed circuit board into flow block; taking care to properly
position the board as shown in Figure 5-6.
6. Replace three screws and tighten to secure board. Reattach the pump
and multi-pin connectors to the circuit board.
7. Replace cover that was removed in Step 1.
8. Calibrate the instrument per Section 4 Calibration . Note that if a new
sensor is installed without performing a calibration, either the
message “Check Background Calibration” or “Check Leak
Calibration” will appear at the bottom of the LCD when the
instrument is turned ON.