SST GT814, Design Manual

September, 2015 

814-15

MODEL GT814 NOVA-Sensor 

ELITE™ 

Toxic Gas Detector

Other Calibration messages

The below listed messages occur during recalibrations. To stop the calibration process at any 

one of these steps, just activate the 

▲MagPoint▲

 on the top side of the enclosure two times. 

The NOVA-Sensor will return to normal operation using the previous calibrations.

HOLD FOR CALIBRATION MODE

RELEASE BUTTON NOW

FINDING ZERO...WAIT

APPLY 50 PPM GAS

GAS DETECTED...WAIT

REMOVE GAS...WAIT

CALIBRATION COMPLETE

Drifting or unstable PPM readings

Check the 2 wires between the sensor head and the electronics module. Screw terminals, 

crimped connectors or wire nuts on these wires must be tight to maintain the low resistance 

connections between the head and the electronics.

Also check the jumper on the two “TOX” pins of the electronics module to be sure that the 

jumper plugs are securely seated on the pins.

False Alarms

If you are having an unreasonable number of alarms, try to verify the gas concentration near 

the detector using a personal gas monitor. If there is no gas, or very little gas, recalibrate the 

NOVA-Sensor 

ELITE.

 If alarms still occur, the sensor head has probably lost sensitivity, and 

the detector has tried to compensate by increasing the amplifier sensitivity. In that case, the 

sensor fuel cell should be replaced and a new calibration performed.

Transient Interference or Power Surges

Transient voltage suppressors in the NOVA-Sensor 

ELITE

 protect the electronics from 

transients that may be induced into the field wiring during operation. The terminal marked 

CHASSIS in the NOVA-Sensor is factory connected to the 24VRET terminal to complete the 

suppression path. In areas where there are severe high energy transients, including those 

caused by lightning, you may get more effective transient suppression by removing the factory 

jumper and connecting the CHASSIS terminal to the earth grounding screw in the detector 

enclosure. 

!

WARNING: The above change can be made only if the enclosure is firmly connected to 

earth ground and the voltage measured between the earth ground screw and the 24VRET  

terminal is not greater then 2.0 volts DC.