How do I know what the sensor to abort gate distance should be?

Dividing the air velocity (in feet per minute) by two gives the sensor-to-abort gate distance in feet.

Air velocity feet-per-second divided by 2 (1/2 second) = sensor to abort gate distance in feet.

Case and point: If you are running your return air velocity at 3000 FPM your sensor to abort gate distance would be 25’. With the less expensive gates that does not have the heavy gates and spring assist, the sensor to abort distance is closer to 50’ needed. This can be a real problem due to the fact that most people do not have that much distance.