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1.
SENSOR AND PUMP INSTALLATION
To install a new sensor or pump follow these steps while referring to Figure 10:
1. Power OFF the instrument, remove the batteries, and with a box wrench unscrew the
inlet port and filter assembly.
2. Remove the six recessed Phillips screws from the back of the instrument case and lift
the top cover off the case. Do not remove the two large Phillips screws flush with the
back of the case, unless installing a new pump.
3. Place the instrument on a flat surface and remove the two Phillips screws located near
the end of the handle. Carefully lift the circuit board out of the case.
4. If the methane sensor is to be replaced, remove the two Phillips screws holding the
old sensor and unplug the 10 pin connector on the end of the sensor cable. Replace
the old sensor with the new and connect and secure as before.
5. The oxygen and CO sensors are replaced by unplugging the old sensor from the
circuit board, recovering the black gasket on the end of the sensor and replacing it in
the sensor well, and inserting the new sensor into the sockets on the circuit board.
6. The pump is replaced by removing the two large Phillips screws flush with the back
of the case (see Step 2 above), removing the manifold from the bottom of the case,
and unscrewing the four screws which secure the pump gasket, pump plate,
diaphragm, and piston to the manifold. Usually replacing the pump plate is sufficient
to restore operation. Reverse the process for reinstallation.
7. The pump motor can be replaced by following the procedure in Step 6 and then
removing the four Phillips screws which secure the pump motor to the mounting
bracket. Reverse the process with the new motor.
8. Verify that the manifold, methane sensor, pump, and pump motor are securely
mounted to the bottom of the case and the sensors appropriate to the instrument are
plugged into the circuit board.
9. Align the cables to avoid the pump and guide the battery board into the two grooves
on the left and right side of the handle. Lower the main circuit board until it rests on
all the bosses.
CAUTION: Crossed wires trapped between the main circuit board and the intake manifold
will prevent the board from seating properly and may lead to intermittent contact
of sensors with their sockets on the circuit board.
10. Secure the two Phillips screws on the right and left side of the circuit board toward
the end of the handle.
11. Replace the top cover of the case and secure it with the six Phillips screws.
12. Replace the inlet port and filter assembly with a box wrench and replace the batteries.
PART 4. MAINTENANCE
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