Pentair FNS Plus Filter Lid Assembly, 50/100 sq ft | 178553 Oval A working check valve helps

A working check valve helps protect heaters

supporting overall system performance

this assembly is perfect for traditional

Their Crystal Water DE filters are known for predictable performance and long service life

Pentair FNS Plus Filter Lid Assembly, 50/100 sq ft | 178553 Oval A working check valve helpsWhat This Part Is Used For Pentair 178553 Lid Assembly CNC, 50 100Sqft, FNS Plus is a replacement lid for compatible FNS Plus 50Sqft and 100Sqft filter models. It seals the cartridge filter housing during operation. Why This Part Matters Maintaining a proper seal prevents air intrusion and water leaks. A damaged lid can reduce filtration efficiency and system pressure. Replacing the assembly restores normal filter performance. Key Features and