Clack WS1 CI Filter Valve Air draw Elbow with internal check valve

The Clack WS1 CI Filter Valve Air Draw Elbow with internal check valve, available from WrekinWater, is the small fitting that lets an air-injection filter valve draw a precise pocket of air into the tank on every regeneration, while its built-in check valve stops water being pushed back the wrong way into the air system. It's a common wear part on aeration-style iron, manganese and sulphur removal filters built around the Clack WS1 CI valve.

Technical specifications

Symptoms that mean you need this part

• Reduced air pocket in the filter tank, causing iron or manganese to break through into your water
• A return of sulphur/rotten-egg smell that the filter had previously been removing
• Water or moisture appearing in the air draw tubing or venturi assembly where it shouldn't be
• Visible cracking, discolouration or a stiff/stuck check valve flap on the existing elbow

Why it fails / why it matters

The internal check valve disc is a small, flexible piece of rubber or plastic that opens and closes thousands of times over the life of the filter, and like any wear item it can harden, warp or get fouled with iron/manganese sediment until it no longer seals properly. Once it fails, air draw either stops working (so the tank loses its treatment air pocket) or water is allowed to pass back into the air system, both of which stop the filter from oxidising and removing iron, manganese or sulphur effectively.

Why buy this from WrekinWater

As specialists who've served more than 50,000 customers over 15 years from Bettisfield, Shropshire, WrekinWater stocks the specific small parts — like this WS1 CI air draw elbow — that keep aeration filters performing correctly, alongside our wider range of Pentair Fleck, Autotrol, Clack and Kinetico parts. We're rated "Excellent" on Trustpilot and operate as UK Company No. 11000488, so you can order the right part with confidence it will fit.

How to fit it

1. Turn off the water supply to the filter and relieve pressure via the valve's manual regeneration or bypass.
2. Locate the air draw elbow on the top of the WS1 CI valve body, typically connected to the air line/venturi tube.
3. Disconnect the air line tubing and unscrew or unclip the old elbow from the valve port.
4. Check the O-ring or seal on the new elbow, then fit it into the valve port and reconnect the air line tubing.
5. Ensure the check valve disc moves freely and is orientated correctly to allow air in and block water out.
6. Restore the water supply, run a manual regeneration, and confirm the air pocket is being drawn correctly on the next cycle.