Clack Separate Source MAV Kit for WS1" and WS1.25" Valves with 1.5" BSP Tails

The 10440000348 c0002 is a Separate Source Motorised Alternator Valve (MAV) kit for Clack WS1 and WS1.25 control valves, supplied with 1.5" BSP tails. It's used on duplex (twin-tank) softener installations fed from two separate water sources, automatically switching flow between tanks so one can regenerate while the other stays in service, without ever mixing the two supplies. Because this kit is central to how a duplex system is plumbed, wired and sequenced, WrekinWater recommends it's fitted by a competent installer familiar with duplex Clack systems, and stocks the kit ready for despatch.

Technical specifications

Symptoms that mean you need this part

• The alternator valve is failing to switch between the two tanks, leaving one tank permanently in or out of service
• One tank isn't coming online during the other's regeneration, interrupting continuous supply
• The MAV motor has burnt out, seized, or no longer responds when the controller signals a switch
• The valve is allowing simultaneous flow from both sources when it should be isolating one at a time
• You're setting up or upgrading a duplex installation and need a separate source MAV kit rather than a standard alternator

Why it fails / why it matters

In a duplex system drawing from two separate sources, the MAV is the component that physically directs flow to one tank at a time, switching over so the other can regenerate without ever cross-connecting the two sources or leaving the site without softened water. The motor, gearing and valve seats inside the MAV are worked every time the system alternates, and over years of cycling the motor can burn out, gears can wear, or the valve seats can degrade to the point where switching becomes unreliable or incomplete. Because a fault here affects how the whole duplex system sequences and protects against source mixing, the MAV kit is typically replaced as a complete assembly rather than repaired part by part.

Why buy this from WrekinWater

WrekinWater has supplied Clack valve and duplex system components to installers and commercial customers for over 15 years from its Bettisfield, Shropshire base, and stocks specialist parts like this Separate Source MAV kit alongside its wider Clack range. Orders are processed quickly and the business is rated Excellent on Trustpilot, which matters when a duplex system's continuous supply depends on the alternator working correctly.

How to fit it

1. Confirm your system uses WS1 or WS1.25 valves with 1.5" BSP tails and a genuine separate source configuration before ordering
2. Arrange for a competent installer to isolate both sources and the control system before removing the existing MAV assembly
3. Fit the new MAV kit and tails, checking the source and tank connections match the original pipework layout
4. Reconnect and check the electrical wiring or control cabling to the alternator motor as specified for your controller
5. Have the installer test the switching sequence manually to confirm the valve alternates correctly between sources and tanks
6. Run the system through a full automatic cycle and confirm no cross-flow occurs between the two separate sources before returning to normal operation