Alex-Tronix Since 1977


F2 AC/DC/DCL Programming

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Select solenoid output on back of circuit board. For 24 V AC solenoid, slide switch toward edge of circuit board. For DC, slide toward center.


Program PERIODIC, FLUSH, and DWELL times on rotary switches.


Adjust PD gauge to filter's recommended pressure differential setting.


A backwash cycle can be initiated manually, by PD, or by the PERIODIC time setting. Any backwash start resets the periodic time.


PD switch must make contact continuously for 30 seconds before it can start a cycle. When PD is activated, display shows I/PD (Idle with PD) and PD Led is on. When three consecutive backwashes triggered by PD are completed, the alarm output comes on and display flashes PD ALARM. To reset alarm, press button for one second while controller is in IDLE.


There is a three digit backwash counter on the display. To reset the count, press the COUNTER RESET button for one second while in IDLE.


Whenever the output fuse is blown, the display will show !FUSE! and the PD and DWELL lights flash. To reset, turn off power, and replace fuse.


The fuse for the electronics is between the front panel and circuit board. To replace, remove the front panel and replace with a 1 amp 5x20 mm fuse. This fuse rarely needs replacement, but is available at Radio Shack if needed.


The master valve output is marked M on the terminal block. It comes on at the start of each backwash to close a field valve to maintain sufficient backwash water pressure, and goes off when the controller returns to IDLE.


During power failure, controller retains the backwash count and resumes with tank that was backwashing prior to power failure.



  • Do not connect 230V AC to a 115V AC transformer (50 or 60 Hz OK).

  • Do not exceed the 1.5 amp output current rating for a standard model.

  • Check output switch for correct match for 24 V AC or 12 VDC solenoids.

  • With 12 VDC input, only use first two terminals. The third terminal is not used. Output switch must be in DC position with DC input.