Netafim Backflush Controller 24VAC for Mains-Powered Filter Pairs
Where a filter pair sits beside the pump house, mains power is the simplest supply for its flushing valves. The Netafim 31NBCAC2, item 00105-006200, takes 110 or 220 volts AC through an internal transformer. That transformer produces the 24VAC that operates the solenoids on its 2 outputs. Its embedded electronic sensor reads the pressure drop across the filters and starts a flush at the chosen set point. Netafim allows a set point anywhere from 0.1 to 2.0 bar, with the display in bar or psi. A timed interval can run alongside, so whichever comes first starts the sequence. The modular board takes plug-in cards of two outputs each, up to 10 in total. Automatic disc, sand media and screen filters can all be run from it. A mounting bracket comes in the box, and the housing weighs just 1.3 lb. The LCD shows flush time, DP set point, actual DP and the flush mode on one screen.
Programming a Two Filter Flush Controller
Four keys handle all programming: ENTER, minus, plus and MANUAL. Pressing ENTER puts the first field into edit mode, and each further press moves to the next field. Flush time per station can be as short as 5 seconds or as long as 6 minutes. Hold ENTER for at least 3 seconds to reach the configuration menu. There the unit detects how many plug-in boards are fitted and assigns outputs from number 1 upward. Answering yes to Main Valve unlocks a pre-dwell between that valve opening and the first filter flushing. Pre-dwell steps run from 5 seconds to 6 minutes, so pressure can build before the first station opens. A looping limit of 1 to 10 consecutive DP cycles flags a filter that is not coming clean. For zero calibration, disconnect both sensor ports so they read atmospheric pressure, then select Yes. Pressing MANUAL starts a sequence on demand, and pressing it again ends one in progress.
Key Features
- 24VAC outputs from mains: Internal transformer accepts 110 or 220 VAC, 50 or 60 Hz.
- Two backflush outputs: Expandable in two-output plug-in cards to a total of 10.
- Embedded DP sensor: Set point 0.1-2.0 bar (1-30 psi), shown in bar or psi.
- Four-key LCD programming: ENTER, minus, plus and MANUAL keys.
- Main valve and pre-dwell: Optional main or pressure sustaining valve with pre-dwell up to 6 minutes.
- Looping alarm: Detects repeated DP cycles past a 1-10 limit.
Technical Specifications
| Specification | Value |
|---|---|
| Item Number | 00105-006200 |
| Model | 31NBCAC2 |
| Outputs | 2, 24VAC solenoids |
| Power Source | 110 or 220 VAC, 50 or 60 Hz, internal transformer to 24VAC |
| DP Input | Embedded electronic analog DP sensor or external dry-contact DP switch |
| DP Set Point | 0.1-2.0 bar (1-30 psi) |
| Flush Time per Station | 5 s to 6 min |
| Flush Interval | 5-60 min in 5 min steps; 2, 3, 4, 5, 6, 8, 12, 18, 24, 72 or 120 h; or DP only |
| Pre-Dwell (Main Valve) | 5-55 s, or 1-6 min in 0.5 min steps |
| Dwell Between Stations | 5-60 s |
| Looping Limit | 1-10 consecutive DP cycles, or off |
| Expansion | 2-output plug-in cards, up to 10 outputs |
| Operating Temperature | 32-140°F (0-60°C) |
| Dimensions | 9-1/2 in H x 5-5/8 in L x 3-1/4 in D |
| Weight | 1.3 lb |
| Included | Mounting bracket |