SENSOR AND PUMP MAINTENANCE
6-3
Sensor
Figure 6-2
Detailed Sensor Assembly of IAQRAE
8. Turn IAQRAE on. The microprocessor will automatically
recognize the sensors installed and configure the monitor
accordingly.
Special Bias Voltage for Toxic Gas Sensors
The NO and NH
3
sensors require a special 300 mV bias
voltage to operate. Only the toxic gas sensor socket provides
such a special bias voltage. There is a pin jumper located on
the edge of the analog PCB next to the bottom of the housing.
When an NO or NH
3
sensor is plugged into the sensor socket,
it is necessary to switch the jumper to enable the bias voltage.
During the power on sequence, the microprocessor will check
the sensor ID and the bias voltage. If the NO or NH
3
sensor is
plugged into the wrong sensor socket or if the jumper is not
switched on, an error message will appear. (Note: When the
jumper is switched on, the bias is off.)
Mounting
Screw
Oxygen Sensor
Base Plate
Humidity-Temp
Sensor
Gas Plate
Pump
PID Sensor
PID Sensor
Gas Plate
CO
2
Sensor