The Watts FM20041-B is a precision-molded Buna-N O-ring designed specifically for Flow-Max housing assemblies to maintain leak-free seals under pressure. This flat gasket construction ensures reliable performance in residential and light commercial water filtration applications.
SPECIFICATIONS
Technical Details
| Manufacturer | Watts |
| Model Number | FM20041-B |
| Material | Buna-N (Nitrile Rubber) |
| Gasket Type | Flat O-Ring |
| Compatible Housing | Flow-Max Series |
| Temperature Range | 40°F to 180°F |
| Application | Pressure Housing Seal |
| Replacement Interval | Every 2-3 filter changes or annually |
INSTALLATION & USE
Replacing Your Flow-Max O-Ring
- Depressurize the system and remove the Flow-Max housing sump from the cap assembly
- Remove the old O-ring from the groove and clean the seating surface with a damp cloth to remove debris or calcium deposits
- Lightly coat the new Buna-N O-ring with food-grade silicone grease and press evenly into the groove
- Reassemble the housing, hand-tighten firmly, then pressurize slowly while checking for leaks
COMPATIBILITY
Flow-Max Housing Systems
This FM20041-B O-ring is engineered exclusively for Watts Flow-Max filter housings. The Buna-N material provides excellent resistance to water, mild acids, and chlorinated water supplies, making it ideal for municipal and well water applications. Not compatible with petroleum-based fluids or applications requiring EPDM or Viton seals. Always verify your housing model before ordering replacement gaskets to ensure proper fit and seal integrity.
🔧 Apply a thin layer of silicone grease to the O-ring before installation to prevent pinching during assembly and extend seal life. Never use petroleum jelly, which degrades Buna-N rubber over time.
