Olyflow U-Flow Seals

U-Flow Seals are mechanical compression seals by OMG designed for retrofit roof drains in 3-, 4-, 5-, and 6-inch sizes. They use tough nylon flanges, EPDM gaskets, and stainless steel screws to create a watertight connection inside the existing pipe, preventing vertical movement and water backup damage. The seal is activated using the U-Flow screwdriver tool which compresses the thermoplastic seal until it expands and locks in place.

Key Features

• available in 3-inch, 4-inch, 5-inch, and 6-inch sizes to match existing drain pipes
• nylon flanges, EPDM gasket, stainless steel screws for durability and corrosion resistance
• meets or exceeds the ANSI/SPRI RD-1 standard for retrofit drains (backflow prevention)
• installs from rooftop without disturbing plumbing below
• activation via tightening screws with U-Flow screwdriver for watertight seal

• product name: U-Flow Mechanical Seal
• item numbers: UF3 (3-inch), UF4 (4-inch), UF5 (5-inch), UF6 (6-inch)
• drain sizes: 3-inch, 4-inch, 5-inch, 6-inch
• pre-expanded outer diameter of seal (approximate):
  • 3-inch: 2.86 in
  • 4-inch: 3.74 in
  • 5-inch: 4.73 in
  • 6-inch: 5.75 in
• fit into pipe inner diameter (approximate):
  • 3-inch: 2.88 in
  • 4-inch: 3.76 in
  • 5-inch: 4.75 in
  • 6-inch: 5.77 in
• fully expanded diameter (approximate):
  • 3-inch: 3.40 in
  • 4-inch: 4.40 in
  • 5-inch: 5.40 in
  • 6-inch: 6.40 in
• materials: thermoplastic (body/flange), EPDM rubber gasket, stainless steel screws
• activation: requires U-Flow screwdriver tool for tightening seal screws in sequence
• screw count per size:
  • 3-inch & 4-inch sizes have three screws each
  • 5-inch & 6-inch sizes have four screws each
• weight per unit: approx. 1 lb each

• Insert the narrow end of the U-Flow Seal into the bottom of the drain stem.
• Use the U-Flow screwdriver to tighten the internal screws, accessible from top of drain, gradually tightening few turns per screw in sequence.
• Continue until the seal expands and locks to the drain stem, ensuring no vertical movement is possible.
• Place the drain assembly (with seal installed) inside the existing drain pipe.
• Tighten screws again in sequence so the compression ring (lowest part of seal) binds uniformly against the old pipe walls.
• Inspect to verify watertight seal and that there is no vertical movement or leakage.

Q: What drain pipe sizes do U-Flow Seals cover?
A: They cover 3-inch, 4-inch, 5-inch, and 6-inch drains.

Q: What materials are used in the U-Flow Seal?
A: Thermoplastic (nylon) flange, EPDM rubber gasket, and stainless steel screws.

Q: What standard do U-Flow Seals meet or exceed?
A: They exceed the ANSI/SPRI RD-1 standard for retrofit roof drains.

Q: How many screws are used in each seal size?
A: Three screws for 3-inch and 4-inch seals; four screws for 5-inch and 6-inch seals.

Q: What tool is required to install or activate the U-Flow Seal?
A: The U-Flow screwdriver is required.