MAINTENANCE
7-11
7.5 Sampling Pump Replacement
The sampling pump is positive displacement piston pump.
When approaching the end of the specified life time of the
pump, it will consume higher amount of energy and reduce
its sample draw capability significantly. When this occurs, it
is necessary to replace the pump.
1. Turn off power of Multi-gas Monitor.
2. Refer to Figure 7-2, open the monitor cover,
disconnect
the battery pack,
carefully unscrew four No. 2 screws
that hold down the gas piping plate to the analog PCB and
sensors. Remove the gas piping plate.
3. Carefully loosen the connector. Unscrew the two screws
that hold the pump assembly to the gas plate. (For older
model, use a soldering iron to de-solder the two wires
that connect the pump to the PCB. Unscrew the two
screws that holding the pump to the PCB.) Disconnect
the Tygon tubing that connects the pump to the gas inlet
port.
4. Replace a new pump assembly. Connect the Tygon
tubing to the gas inlet port. Solder the pump wire and
screw down the pump assembly to the analog PCB.
5. Refer to Figure. 7-2, replace the gas piping plate and
tighten the four screws to hold down the sensors. Re-
connect the battery pack. Replace the monitor cover.
