The Fleck 2900S is a high-flow, commercial-grade water softener control valve built on a rugged lead-free brass body and paired here with a 12-day mechanical time clock for dependable, schedule-based regeneration. Engineered for large residential, commercial, and light-industrial softeners, it drives proven down-flow (co-current) regeneration, mounts to mineral tanks up to 36" in diameter, and delivers heavy service flows without electronics to fail. This configuration ships complete with a 4C injector, a 1710 plastic brine system with 2.0 GPM refill control, an integral hard-water bypass, and an environmental black cover with a clear programming window.
Key Performance Metrics
Valve Construction & Configuration
| Control Type | 12-day mechanical time clock — regenerates on a fixed calendar, adjustable up to once every 12 days |
| Regeneration Style | Downflow / co-current, 5-cycle |
| Valve Body Material | Lead-free brass, NPT connections |
| Injector | 4C injector |
| Brine System | 1710 plastic brine valve, 1/2" brine line, 2.0 GPM flow control |
| Bypass | Integral hard-water bypass (raw water available during regeneration) |
| Distributor / Riser Tube | 1.9" O.D. pilot, 1-1/2" (38 mm) riser tube |
| Drain Line Connection | 1" NPT (Drain Line Flow Control not included — order to match tank size) |
| Operating Pressure | 20 – 125 psi (1.4 – 8.5 bar) |
| Water Temperature | 34 – 110°F (1 – 43°C) |
| Cover | Environmental black cover with clear window for at-a-glance timer viewing |
| Part Number | FL2510AIO-TC (NC) |
Built for High-Demand Softening
Heavy-Duty Brass Body
A lead-free brass valve body stands up to high pressure, temperature swings, and years of continuous duty far better than plastic-bodied residential valves — the reason the 2900S is a workhorse in commercial installs.
12-Day Time Clock
A simple, rugged mechanical timer regenerates the softener on a set calendar schedule with no circuit boards to fail — ideal where water use is predictable and long-term reliability matters most.
4C Injector
The pre-matched 4C injector draws brine efficiently through the resin bed during regeneration, sizing the eductor to the valve's high flow so the resin recharges thoroughly on every cycle.
1710 Brine System, 2.0 GPM
An external 1710 plastic brine valve with a 2.0 GPM refill control meters the brine draw and tank fill precisely, and services from the outside without pulling the valve off the tank.
Hard-Water Bypass
An integral bypass keeps untreated water flowing to the building during the regeneration cycle, so supply is never interrupted even on a single-tank system.
Environmental Cover
The sealed black environmental cover protects the drive and timer from dust and moisture, while a clear window lets you confirm the program at a glance without opening the unit.
Getting Set Up
- Thread the 2900S onto your mineral tank over the 1-1/2" distributor/riser tube, making sure the riser is cut flush, chamfered, and centered so it seats cleanly in the valve.
- Select and install the correct Drain Line Flow Control button for your tank diameter (sold separately) — this sets the backwash rate that lifts and cleans the resin bed.
- Connect the inlet and outlet plumbing to the brass ports, then run the 1" drain line and the brine line to the 1710 brine system, keeping the drain within the recommended length and rise.
- Plug into 120V power and program the 12-day time clock: set the current time, the time of day to regenerate, and the number of days between regenerations based on your hardness and water usage.
Where the 2900S Fits
The 2900S softener valve is designed for mineral tanks from roughly 14" to 36" in diameter, making it a natural fit for large homes, apartment and commercial buildings, restaurants, car washes, and light-industrial process water. Because this is a time-clock (calendar) control rather than a metered valve, regeneration is triggered by elapsed days rather than gallons used — so it's best where daily demand is steady and predictable. Size your day setting to your water hardness and total usage: aim to regenerate before the resin bed reaches about 75% of its rated capacity so you never let hardness break through, but not so often that you waste salt and water. This unit ships Less Drain Line Flow Control, so be sure to add the DLFC button matched to your tank size, and confirm your incoming pressure and temperature fall within the valve's 20–125 psi and 34–110°F ranges.
Pro Tip: The 2900S brine system and injector service from the outside of the valve, so you can clean or swap the 4C injector, brine valve, and flow controls without breaking any plumbing connections — a big time-saver during routine maintenance or if you ever need to re-size the valve for a different flow.
