FLECK 12281 Top of Tank O ring for Fleck 4600 & 5600 + 9000 Duplex valves

The FL12281 O-ring seals the joint where the Fleck 4600, 5600 or 9000 Duplex control valve threads onto the top of the resin tank, and it's one of the most common causes of a slow drip or damp patch appearing at the base of the valve. WrekinWater stocks this O-ring as a genuine-fit, low-cost replacement to stop leaks at the tank connection without having to replace the valve or tank.

Technical specifications

Symptoms that mean you need this part

• A slow drip or damp patch appearing where the valve meets the top of the resin tank
• Visible water pooling under the softener even when no other pipework is disturbed
• A hardened, flattened or cracked O-ring seen when the valve is unscrewed from the tank
• The leak gets worse after the valve has recently been removed for cleaning or servicing

Why it fails / why it matters

This O-ring sits under compression between the base of the control valve and the threaded top of the resin tank, and it's what stops water forced through the valve under mains pressure from escaping at that joint. Rubber naturally hardens and loses its compression set with age and temperature cycling, so even a valve that has never been touched can develop a slow leak here after several years of service, and any time the valve is unscrewed for maintenance the old O-ring should be replaced rather than reused.

Why buy this from WrekinWater

WrekinWater has served more than 50,000 customers over 15 years and stocks Pentair Fleck, Autotrol, Clack, Kinetico and other major brands, so the FL12281 is readily available whenever a leak shows up at the tank connection. As a family run company based in Bettisfield, Shropshire rated Excellent on Trustpilot, we make sure this small but essential seal is always in stock.

How to fit it

1. Turn off the water supply to the softener and relieve pressure with a manual regeneration.
2. Disconnect the bypass valve fittings and any pipework attached to the control valve.
3. Unscrew the control valve from the top of the resin tank and set it aside carefully.
4. Remove the old, hardened O-ring from the tank thread or valve base groove.
5. Fit the new FL12281 O-ring into the groove, lightly lubricating it with a silicone-based lubricant if available.
6. Screw the valve back onto the tank, reconnect the pipework, then restore the water supply and check for leaks.