The Series A3 is a digital differential pressure control with flow and velocity functionality. The A3 is available with (2) SPDT relays, and a 4-20 mA output. The A3 includes a a LCD programming display.
The Series A4 is a digital differential pressure control with flow and velocity functionality. The A4 is available with (2) SPDT relays, and a 4-20 mA output. The A4 includes a brighter, easier to read OLED programming display.