By Pass Seal Gasket ( old PN 11726, new PN 14015 )
for Fleck Metal By Pass Valves.
Older versions were Brass, or Nickel Plated Brass.
Newer versions are Stainless Steel.
This Seal Gasket works with all versions and both 3/4" and 1" sizes.
WaterSoft PN 20561c280
CUNO ( Aqua Pure ) cross reference part number 55664-148
The common LEAK problem can be easily fixed by replacing this Seal Gasket.
You have four bolts on top and four bolts on the bottom of your By Pass which hold this Seal in place.
Plan on 15 minutes to replace this part.