Fleck Assembly 9000/9100 HW Bottom

Restore proper sealing in the lower section of your Fleck 9000 or 9100 twin-tank control valve with this genuine Pentair Fleck Assembly (9000/9100 HW Bottom). Built for hot water service, this bottom piston and seal assembly is the component that directs water flow through the lower valve ports during service and regeneration. It is part of the Fleck Piston & Seal Kits service family and is specific to the 9000 and 9100 twin-tank valve platform.

The 9000/9100 series is engineered for continuous, alternating twin-tank operation, meaning one tank stays in service delivering treated water while the other regenerates, with no downtime. Because the valve cycles constantly to keep that hand-off seamless, the lower assembly sees heavy, ongoing use. Over time the seals harden and the piston surface wears, allowing internal bypass that quietly reduces softening or filtration performance even though the valve appears to be working. This service assembly brings the lower valve back to factory specification and eliminates that bypass.

Twin-Tank Reliability

• Genuine Fleck 9000 / 9100 lower (bottom) assembly
• Rated for hot water (HW) applications
• Listed under Fleck Piston & Seal Kits service category
• Restores positive sealing and prevents internal leakage
• Keeps twin-tank systems delivering uninterrupted treated water
• Direct fit for 9000 and 9100 control valves

Because 9000-series valves provide soft or filtered water around the clock with no interruption during regeneration, keeping the lower assembly in good condition is key to their signature no-downtime performance. Installers typically refresh both the upper and lower assemblies during a complete rebuild, since the two wear in parallel over the life of the valve. To service the unit, take the system out of service, depressurize it fully, and follow Pentair's documented Fleck procedure for the 9000/9100. Lubricate the new seals with an approved silicone lubricant during reassembly, verify the piston moves freely, and the valve will return to clean, leak-free cycling. Keeping the lower assembly fresh is a small investment that pays off in the continuous, dependable performance the 9000 and 9100 platforms are known for, and it helps avoid emergency service on systems that are expected to run without interruption. For installers maintaining commercial accounts where uninterrupted water is a contractual expectation, this lower assembly is a routine, high-value part to keep stocked for fast, scheduled rebuilds.