A two channel monitor with automatic solenoid valve on/off switch. Its features also include low current draw, plug-in sensors, display module fault light/alarm and fault light/alarm to indicate a malfunction in either one of the sensors. A "press to test" button for each channel confirms function. The system is calibrated at 20% LEL (lower explosive limit) to eliminate most nuisance alarms while allowing enough time to take action. 4 3/4" x 3 3/4" x 7/8".