The gas expansion module only operates in a pumped mode. The module has one pump inlet that enables a single EXO to remotely sample an area using tubing. A pump inlet filter must be installed before operating the gas expansion module to prevent pump blockages and maintain the pump in good condition.

When EXO is powered on and completes the start-up sequence, the pump automatically turns on. EXO purges for two minutes to clear out any gas from the sensors, then continuously draws in air through the inlet.