Heath Consultants Hi Flow Sampler - Manual (Page 48)

Maintenance Hi Flow

Sampler
48 Instruction 0055-9017
4.5 Gas Sensor Replacement
Replace a gas sensor when it fails to calibrate per Section 3 Calibration. The gas sensors
are located inside their associated flow blocks of the leak-gas and background-gas
sensor assemblies. See Figure 4-5.
Figure 4-5. Leak Gas & Background Gas Sensor Assemblies
Equipment Required:
• Medium Phillips Head Screwdriver
• Replacement Sensor (P/N 0055-0040)
Procedure:
1. Remove cover per Section 4.3.
2. Remove the pump connector and multi-pin connector from printed circuit board,
noting orientation of connectors. See Figure 4-6.
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 4-6.
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 3 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.