Netafim Alex-Tronix Backflush Controller, 8 Station, 24VAC/12VDC/12VDCL Outputs

Alex-Tronix 8 Station Backflush Controller for Large Filter Banks

A long row of media or disc tanks needs a controller that walks through every unit without starving the field downstream. The Alex-Tronix F8AC/DC/DCL-D handles up to 8 tanks from one front panel, washing them in sequence. Stations are enabled with an eight-position DIP switch, and any combination may be used. Its master valve output can close a field valve while the bank flushes, keeping pressure high enough to clean each element. A dwell setting of 5 to 180 seconds lets each valve shut before the next one opens. Every tank gets the backwash time set on the front dials, anywhere up to 15 minutes plus 60 seconds. The periodic interval runs from a quarter hour up to two days, and it restarts after every backwash. A pressure differential signal can start a cycle sooner, once the PD delay confirms the reading is genuine. The electronics sit behind a swing-out panel in a powder-coated, locking steel box. Alex-Tronix builds the controller in Fresno, California and backs it with a two-year warranty.

Powering an Alextronix Backwash Controller in the Field

Remote filter stations often have no mains supply, which is where the DC and latching options earn their keep. The DCL build drives two-wire latching solenoids. It runs from a 12 VDC battery. Alex-Tronix rates a fully charged 80 amp-hour car battery at about four months of service without a panel. Pair a 7 amp-hour rechargeable battery with a 5 watt solar panel and it runs continuously through up to five sunless days. Keep battery voltage between 12 and 15 VDC, and check the polarity before power is applied. Connect each solenoid's red lead to the common terminal and its black lead to the station terminal. Slide the latching DIP switch while the display reads IDLE, and a small L confirms the mode. Where mains power is on hand, the standard transformer takes 115 VAC and supplies the 24 VAC outputs. An alarm flashes after three or more consecutive PD-started backwashes, pointing to a filter that is not cleaning. Filtering continues during the alarm, and the A terminal can drive a relay for a light or bell.

Key Features

• Up to eight stations: DIP-selectable tanks in any combination, plus a master valve output.
• Battery and solar ready: DCL build runs two-wire latching solenoids from a 12 VDC battery.
• Wide timing range: Periodic 1/4-48 hours, backwash to 15 minutes plus 60 seconds, dwell 5-180 seconds.
• Surge protection: PD delay of 0-180 seconds before a pressure-started cycle.
• Alarm with relay output: Flags three consecutive PD backwashes while filtering continues.
• Power-failure memory: Keeps the count and resumes on the same station.
• Locking steel box: Powder-coated enclosure with swing-out panel.

Technical Specifications