B26 - 15mm check Valve (Non Return Valve NRV)

The B26 is a 15mm check valve, or non-return valve, that allows water to flow in one direction only, commonly fitted on the brine or bypass line of a water softener to stop water flowing back the wrong way. WrekinWater supplies it as a straightforward replacement where an existing check valve has failed or is missing. Fitted correctly, it protects the rest of the system from backflow.

Signs you need this part

• Water or brine appears to be flowing backwards through the line the valve is fitted on.
• The softener isn't drawing brine correctly during regeneration.
• The valve has visibly seized, cracked, or the internal flap no longer moves freely.
• You're replacing pipework and the original check valve is missing or damaged.

A check valve contains a small internal flap or disc that opens to let water flow one way and closes to stop it reversing, and it's this closing action that protects the rest of the system from contamination or lost pressure through backflow. Over time the internal flap can stick, wear, or fail to seat properly, especially where it's regularly exposed to brine, which is more aggressive on internal components than mains water. A failed check valve can let water flow the wrong way at exactly the point in the softener's cycle it's meant to prevent it.

WrekinWater is a family-run water treatment specialist based in Bettisfield, Shropshire, rated Excellent on Trustpilot, with 15 years' experience and more than 50,000 customers served. We stock the individual valves and fittings used across the softener systems we sell.

How to fit it

1. Isolate the water supply and relieve pressure in the pipework where the valve sits.
2. Note the flow direction arrow on the old valve before removing it.
3. Cut out or unscrew the old check valve from the line.
4. Fit the new B26 valve with the flow direction arrow matching the direction of normal flow.
5. Secure the connections on both sides, using PTFE tape on any threaded joints.
6. Restore the water supply and check for leaks and correct one-way operation.