MAINTENANCE & TROUBLESHOOTING
4-2
WARNING!
Maintenance should be performed only by a qualified
person who has proper training and fully understands the
contents of this manual.
The following guidelines should be followed when
changing components:
1. Turn off the unit and unplug the charger before changing a
battery. The battery pack screws can be tightened or
loosened using a coin.
2. When changing a sensor, detach the battery first and then
open the sensor cover only, not the housing top.
3. Identify the location of a specific sensor and pay attention
to the sensor pin orientation when removing and plugging in
sensors.
4. The NO and NH
3
sensors require a special 300 mV bias
voltage to operate. A “dip switch” located on the PCB next
to the Tox 1 and 2 sensor positions must be placed in the
“ON” position for the corresponding sensor to enable the
bias voltage when an NO or NH
3
sensor is installed. The
default setting of bias OFF is used for most sensors.
4.1. Battery Charging Operation
WARNING!
To reduce the risk of ignition of hazardous atmospheres,
recharge battery only in area known to be non-hazardous.
Remove and replace battery only in area known to be non-
hazardous.
Ne charger les batteries que dans l’emplacements
désignés non-dangereux.
