MAINTENANCE
7-4
7.2 Sensor Replacement
The toxic, combustible and oxygen sensors all have an
expected operating life. Under normal operating condition,
most sensors will lose its original sensitivity after the
expected operating life and needs to be replaced.
Each sensor module in VRAE includes a non-volatile
memory that records the manufacturing date of the sensor.
In the diagnostic mode, the microprocessor will check the
date code and display the expiration date of each sensor.
The user should replace the sensor when the current date
exceeds the expiration date of a sensor.
Sensor Replacement Procedure
The oxygen and combustible sensor each has its unique
sensor sockets in the VRAE monitor. The three toxic sensor
sockets in the VRAE monitor allow the users to plug in any
three sensors selected from the series of toxic sensors
offered by RAE Systems Inc.
1. Turn off power of the VRAE.
2. Refer to Figure 7.1, open the battery cover by unscrew
the two screws from the bottom of the monitor case.
Remove the battery pack.
3. Open the bottom cover of the monitor case by removing
the 6 screws that holds the bottom case.
