Piston Assy, 2815 Hard Water Bypass

The genuine Pentair Fleck Piston Assembly for the 2815 Hard Water Bypass directs flow inside the 2815 control valve so that, during regeneration, untreated hard water can bypass to the service line rather than passing through the media being regenerated. This piston is the moving heart of that bypass function and is specific to the 2815 valve platform.

Hard Water Bypass Explained

On a typical single-tank system, water service is normally interrupted while the valve regenerates, since all flow is being directed through the cycle stages rather than to the house. A hard water bypass piston changes that by routing raw, untreated water around the tank during regeneration, so a household or facility still has water flow even while the media is being recharged. The trade-off is that the water delivered during that window is temporarily untreated, but for many larger applications, continuous availability of water is well worth it. For this routing to work cleanly, the piston's seals and lands must be in good condition so the bypass path opens fully and the treatment path closes off properly.

• Genuine Fleck 2815 hard water bypass piston assembly
• Enables raw-water bypass during regeneration
• Maintains water availability while the media regenerates
• Restores correct internal flow routing in the 2815
• Direct replacement for worn bypass pistons
• Built for larger residential and commercial systems

The Fleck 2815 serves larger residential and commercial systems where uninterrupted flow during regeneration is genuinely valuable, such as facilities that cannot tolerate a service interruption. A worn bypass piston can cause internal leakage, improper routing, or a bypass that fails to open or close fully, defeating the very purpose of the feature. Replacing the piston restores the intended operation. To service it, take the unit out of service, depressurize the valve fully, and follow Pentair's documented 2815 procedure. Replace the associated seals and spacers at the same time, lubricate them with an approved silicone lubricant, and verify the piston moves freely through its full travel before returning the system to service. Because the hard-water bypass is a defining feature of systems chosen for uninterrupted flow, keeping the piston that controls it in good condition is essential to delivering the continuous water availability those installations were designed to provide.