Typically near the fill port an Overfill Alarm Station is installed. This control station is used to alert the delivery truck driver that the tank is full and that tank filling should stop immediately. The panel will include a red light for each tank being filled and an alarm horn. The driver will be able to silence the alarm, but the red high level alarm light will stay lit till the high alarm is cleared, normally by using some of the oil in the main tank. Normally the high level is set at 90%, depending on the installation. The Overfill Alarm Station is only looking for an alarm contact closure to sound the alarm. The red light will clear once this contact opens. Also included is an alarm test button that when pressed will sound the alarm horn and light the red light.
With some systems the overfill alarm station functions are built into the fill box described above, but in others where the fill port may be just an opening in the top of a buried tank, this overfill alarm station functions by itself and is located within sight of the driver.
Subject to Change without notice