Netafim Alex-Tronix Backflush Controller, 4 Station, 24VAC/12VDC/12VDCL Outputs

Alex-Tronix 4 Station Backflush Controller for Filter Batteries

Disc and screen filter batteries clean best when each tank gets its own short, full-pressure flush. This Alex-Tronix F4AC/DC/DCL-D, built in Fresno, California and supplied through Netafim, sequences that job across up to 4 tanks. A DIP switch on the back of the board turns each station on, so a three-tank battery leaves one station off. A separate master valve output energizes as the cycle starts and drops out when the last station finishes. Closing a field valve this way holds pressure on marginal systems so the screen, media or disc element flushes properly. Cycles start on the periodic dial, adjustable from 1/4 to 48 hours, on a pressure differential signal, or from the manual start button. Backwash time combines a minutes dial of 0 to 15 and a seconds dial of 0 to 60. Dwell between tanks runs from 5 to 180 seconds, letting one valve close before the next opens. The same unit accepts 115 VAC through its transformer or 12 VDC from a battery. Outputs drive 24 VAC, 12 VDC or two-wire 12 VDC latching solenoids at up to 1.6 A.

Programming an Alex Tronix Filter Controller

Mount the locking steel box on a wood post or panel, or on a bracket at the filter manifold. Run 115 VAC in through 1/2 in conduit. Wire the supply with 14 or 16 gauge cable. Alex-Tronix suggests a flush every 2 hours for screen or disc filters and every 6 hours for media. Their starting backwash times are 30 seconds for screen tanks and 2 minutes for media, with dwell at 15 and 30 seconds. Set the PD gauge in the 6 to 8 psi range for most systems, then tube the manifold to its HI and LO ports. Three small switches set the PD delay from zero to 180 seconds, which keeps surges from starting a needless cycle. Three more set a pre-dwell of up to 105 seconds, giving the first tank the same flush pressure as the rest. The display reads IDLE while filtering and shows the backwash count plus the time since the last cycle. After three consecutive PD-started backwashes the alarm flashes, and the A terminal can trigger a light or bell. On a power cut the count is kept, and an interrupted cycle resumes on the same station.

Key Features

• Up to four stations plus master: DIP-selectable tanks with a master valve output during each cycle.
• Three ways to start: Periodic dial, pressure differential signal or manual start.
• Pre-dwell and PD delay: Pre-dwell 0-105 seconds and PD delay 0-180 seconds, set by DIP switch.
• AC, DC or latching: 115 VAC or 12 VDC input; 24 VAC, 12 VDC or 12 VDC latching outputs.
• Alarm output: Flashes after three consecutive PD backwashes; A terminal drives a relay.
• Status display: Backwash count, elapsed time since the last cycle and current station.
• Locking steel enclosure: Powder-coated box with a swing-out front panel.

Technical Specifications