Clack WS1 softener valve (CS, CI, EI and twin variants): quick sheet

Covers: Clack Water Specialist WS1 and WS1.25 control valves on residential softeners and backwashing filters: CS (non-programmable OEM-set), CI and EI programmable boards, and twin/alternating setups with an MAV. Sold under many dealer brands; recognised by the red bypass knobs and the Clack/Water Specialist face.

Cross-checkedBrands: Clack9 components

The WS1 is a reciprocating-piston valve with a one-piece seal/spacer stack and a DC drive. It is common in dealer and online systems because it handles 6"-21" tanks and can refill either before or after regeneration. Service problems usually come down to the drive (stall codes 1001-1003), a piston stack fouled by iron or sand, a plugged injector, or a missing/plugged drain or refill flow control.

Safety first

Bypass and relieve pressure before removing the drive cap
Unplug the power supply before removing the board or motor
Do not use petroleum lubricants on seals

How it works

A drive motor turns a gear train that pushes the main piston (and on softeners a second, regenerant piston) along the spacer stack. An optical sensor on the board reads the gear position, so the board always knows where the piston is; if the expected movement is not seen in time it posts a 1001-1004 family code.

A softener cycle is backwash (upflow), regenerant draw and slow rinse (downflow through the injector), an optional second backwash, fast rinse, and refill. Each step is set in minutes in the OEM setup. Refill can be programmed as a post-fill (end of regeneration) or a pre-fill with a dwell, which is why some Clack brine tanks look nearly dry between regenerations by design.

Metered units count gallons with a turbine in the outlet and calculate reserve automatically when capacity is set to AUTO; time-clock units use days. Days override is adjustable 1-28 days. The valve keeps programming in non-volatile memory; current boards hold the clock about 8 hours on a coin cell.

Flow is set by two small washers: a drain line flow control (DLFC) sized to the tank's backwash rate, and a refill flow control in the brine elbow. Valves ship without a DLFC; one must be installed for the tank size.

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Official manufacturer documentation

Always confirm values against the tech sheet for the exact model.

OnCall Tech is a reference tool for trained technicians and can make mistakes. Always disconnect power and confirm with the manufacturer's documentation before you work. © 2026 OnCall Tech. Original content; not a reproduction of any manufacturer document.

Diagnostic guides for this appliance

Guide · Water Softener

Softener brine tank stays dry (no water to make brine)

First decide whether the tank is supposed to look dry: some valves (Clack pre-fill, some cabinet units) keep little water between cycles, while Fleck 5600-style post-fill units should hold several inches of water after every regeneration. If it should have water, the usual causes are a plugged brine line flow control, a stuck float/brine valve, a brine line leak sucking air, a too-short fill time, or a valve that never reaches the refill step.

8 steps ~45 minmoderate

Guide · Water Softener

Softener keeps running water to drain (stuck in regeneration or leaking in service)

Flow to drain is normal only during a regeneration (usually about 1.5-2 hours, overnight). If it continues, either the valve is stuck in a regeneration position (power loss, stalled motor, seized piston) or worn piston seals are leaking service water to drain. Bypass first to stop the waste, then decide which it is.

8 steps ~60 minmoderate

Guide · Water Softener

UV water system alarm, beeping or lamp out

Most UV alarms are the lamp-life countdown reaching zero or a timer that was not reset after a lamp change. A true lamp-failure alarm, a ballast fault or a low-UV reading on a monitored unit means water may not be disinfected: treat the water as unsafe until the cause is fixed and the plumbing is shocked. Exact alarm patterns and reset steps differ by controller, so confirm on the unit's label or manual.

8 steps ~60 minmoderate

Other water softeners & filters manuals

Manual · Water Softener

Fleck 5600SXT metered softener valve: quick sheet

Fleck 5600SXT electronic control on the 5600 piston valve (3/4" or 1" bypass), downflow and upflow softeners and timer filters. Sold under many dealer and online brands; the valve is identified by the Fleck label and the three-button SXT face (Extra Cycle, Up, Down). Mechanical 5600 timers share the valve body but not the electronics.

9 components7 common failuresFleck (Pentair)

Manual · Water Softener

Whirlpool (WHES) and GE cabinet softeners from big-box stores: quick sheet

All-in-one cabinet softeners sold at home centers: Whirlpool WHES series (WHES30/40/44/48 family; built by Ecodyne Water Systems, later Water Channel Partners per the manuals) and GE GXSH/GXMH series. Kenmore cabinet units from the same maker share most of the design. Not for dealer two-tank systems.

8 components7 common failuresWhirlpool, GE

Manual · Water Softener

Whole-house cartridge filters + UV disinfection (VIQUA / Sterilight and similar): quick sheet

Point-of-entry treatment trains on wells and municipal supplies: 10 in and 20 in big-housing sediment and carbon cartridge filters, followed by a stainless UV chamber with a lamp, quartz sleeve and plug-in controller (ballast). Covers non-monitored units (lamp-out indicator only) and monitored units with a UV intensity sensor.

8 components7 common failuresVIQUA, Sterilight, 3M Aqua-Pure, Pelican, Generic big-housing filters