18494 FLECK Injector O Ring Kit for Fleck 4600 & 5600 valves (Obsolete)

The Fleck 18494 injector O-ring kit is the genuine Pentair seal set for the injector housing on Fleck 4600 and 5600 valves — the most commonly searched Fleck brine valve part when a softener stops drawing salt properly. If you're looking for Fleck injector seals, a Fleck 5600 O-ring kit, or a fix for weak brine draw, this is the part. Supplied by WrekinWater, UK stockists of genuine Fleck spares.

Technical specifications

Symptoms that mean you need this part

• Salt level in the brine tank barely drops after a regeneration, even though the cycle runs to completion
• Water that feels 'hard' again within a few days of the softener regenerating
• Spitting, dribbling or an unusual hiss from the drain line during the brine draw stage
• The brine tank slowly overfilling because the system isn't drawing brine properly

Why it fails / why it matters

These O-rings sit directly in the brine path, so they're constantly exposed to concentrated salt solution and thousands of pressure cycles over the valve's life. Salt is mildly corrosive to rubber over time, and the constant on/off pressure eventually causes the seals to compress, crack or swell just enough to lose suction — the injector still looks intact, but it can no longer pull brine efficiently.

Why buy this from WrekinWater

As specialists in Fleck water softener parts for over 15 years, WrekinWater checks fitment against the valve model before it ever reaches your basket — so you're not left guessing which of the many similar-looking Fleck O-ring kits is correct for your 4600 or 5600. Rated Excellent on Trustpilot, with UK stock ready to ship.

How to fit it

1. Turn the valve to bypass before starting any work.
2. Remove the injector cap — usually a single screw or a quarter-turn bayonet fitting on the side of the valve body.
3. Withdraw the injector cage and slide off the old O-rings.
4. Check the injector nozzle itself for scale or grit while it's out — a quick soak in a mild descaling solution clears most blockages.
5. Fit the new O-rings, reassemble the cage and cap, then restore the valve to service.
6. Run a manual regeneration and watch the brine tank level — it should drop noticeably during the brine draw stage, confirming the draw is restored.