Sensor replacement – RKI Instruments Digester Gas Monitor User Manual
Page 88
82 • Sensor Replacement
Digester Gas Monitor Operator’s Manual
Sensor Replacement
This section describes how to replace the sensors in the Digester Gas Monitor. The figure
below shows the flow block that is installed in the Digester Gas Monitor and the location of
each sensor in the flow block.
Figure 23: Flow Block
Replacing the Methane Sensor
1.
Turn off the Digester Gas Monitor
2.
Turn off incoming power to the Digester Gas Monitor.
3.
Open the housing door of the Digester Gas Monitor.
4.
Turn the regulator knob all the way counterclockwise to close the regulator output.
5.
The methane sensor and preamp are located in the lower right corner of the flow block
when viewed from the top. Unscrew the 4 screws that retain the preamp circuit board.
Take care not to lose the flat washer and lock washer under each screw head.
6.
Lift the preamp circuit board away from the flow block.
Be careful not to pull on the cable that connects the preamp circuit to the main circuit
board.
There is a gasket in the bottom of the sensor cavity. Make sure the gasket stays in
place.
7.
Pull the methane sensor off the preamp circuit board.
8.
Plug the new sensor into the preamp board.
CO2 Sensor
Front of Flow
Block W hen
Viewed From
Front of Digester
Methane Sensor
Oxygen Sensor
H2S Sensor