A drain trap’s job is to prevent liquid water, collected from wet compressed air, from invading the compressed air system. It is the system’s last line of defense against the corrosive effects of moisture.

Most conventional drain traps suffer two main drawbacks: lack of reliability and no alarm or back-up in case of failure. Some try to solve these problems with a timer. This solution only works depending on the accuracy of the timing cycle to account for different moisture levels caused by fluctuations in the system’s air flow, temperatures, pressures, and other factors. Since these fluctuations cannot be predicted, the timer-operated trap usually ends up either wasting compressed air or causing a water back-up into the system.