Fleck 28339 Seals & Spacer Kit 3150/3900 Upper Hot Water

WrekinWater stocks the Fleck 28339 Seals & Spacer Kit for the upper piston stack on Fleck 3150 and 3900 hot water softener valves, a genuine Pentair Fleck wearing-parts kit for anyone servicing a commercial or industrial-grade hot water softener before it starts letting untreated water through.

Technical specifications

Symptoms that mean you need this part

• Water weeping from the top of the valve body around the upper stack area
• Hardness breaking through into softened water shortly after a regeneration cycle
• A knocking, popping or hissing noise from the upper valve section during the regeneration cycle
• Visible wear grooves, flat spots or hardened, cracked rubber when the upper seal stack is inspected

Why it fails / why it matters

The upper seal and spacer stack sits closest to the drive assembly and takes constant flexing every time the valve indexes through a regeneration cycle. On hot water duty, sustained elevated temperature speeds up how quickly rubber compounds harden and lose their seal, so the upper stack on a 3150/3900 hot water valve typically needs attention well before the piston or lower components do.

Why buy this from WrekinWater

WrekinWater has supplied genuine Pentair Fleck parts to more than 50,000 customers over 15 years from our base in Bettisfield, Shropshire, and we stock Fleck alongside Autotrol, Clack, Kinetico and other major brands, so this kit is matched correctly to your 3150/3900 hot water valve. We're UK Company No. 11000488 and rated "Excellent" on Trustpilot.

How to fit it

1. Isolate the softener at the inlet, release system pressure, and switch to bypass before opening the valve
2. Remove the valve cover and drive assembly to gain access to the upper piston and seal stack
3. Slide out the upper stack components, noting the order and orientation of each seal and spacer as they're removed
4. Clean the bore and inspect it for scoring or mineral build-up before fitting new parts
5. Lubricate the new seals with a silicone-based lubricant approved for potable water and fit them in the original sequence
6. Reassemble the drive assembly, restore the water supply, and run a manual regeneration to confirm there are no leaks