Marathon 4 in. Pro Flo Aluminum Reroof Drain

The Marathon Pro Flo PFDS-4 Aluminum Reroof Drain is designed for reroof and retrofit systems using the MAXXFLO mechanical seal. Built with a heavy-duty (.081) spun aluminum body, it includes a standard plastic strainer and clamping ring to ensure watertight performance. The 4-inch Pro Flo drain installs quickly without disturbing the existing roof assembly or interior finishes, making it a reliable solution for reroof applications.

Key Features:

• SKU PFDS-4, 4-inch Pro Flo Aluminum Reroof Drain
• Quick and easy installation with MAXXFLO seal
• Heavy-gauge (.081) spun aluminum body
• Standard clamping ring and plastic strainer supplied
• Optional metal strainer and clamping ring available
• Installation avoids disturbing the existing roof assembly

• Part number: PFDS-4 (4″)
• Construction: Heavy-duty gauge (.081) spun aluminum
• Supplied components: Plastic strainer and clamping ring (metal optional)
• Also available: Copper version of drain
• MAXXFLO seal color: Black and yellow
• MAXXFLO seal material: ABS and EPDM rubber
• MAXXFLO seal technical data (4″ size):
  • Weight: 0.55 lb (0.25 kg)
  • Inside diameter: 2.81″ (71 mm)
  • Low temperature impact (ASTM D-2136): −40 °C (−40 °F)
  • Brittle point (ASTM D-746): −57.8 °C (−76 °F)
  • Accelerated weathering (ASTM D-2565 Xenon): minimum 5,000 hours
  • Linear dimension change (ASTM D-1204): 0.0%
  • Change in weight after 24-hour water immersion (ASTM D-570): 0.0%
  • Seal water back-up pressure resistance: 35 kPa (≈ 3.56 m of water)

• Select PFDS-4 for 4-inch outlet applications.
• Insert the MAXXFLO seal into the drain stem; use the castle head/ratchet to expand the seal so it locks into the stem.
• Place the drain assembly into the roof drain pipe.
• Tighten the castle head until the unit is securely fixed and watertight.
• If the leader pipe cannot accept the full stem length, cut the stem leaving at least 2 inches to secure the top of the seal; ensure an opening height of about 4 inches.

Q: What’s included with PFDS-4?
A: A plastic strainer and clamping ring are supplied as standard; metal versions are optional.

Q: What materials are used?
A: The drain body is heavy-gauge (.081) spun aluminum; the MAXXFLO seal is ABS and EPDM rubber.

Q: What sizes are available in the Pro Flo series?
A: PFDS-3 (3″), PFDS-4 (4″), and PFDS-6 (6″).

Q: What is the purpose of the MAXXFLO seal?
A: It locks the drain to the leader pipe and provides watertight performance while resisting water back-up.

Q: Does installation disturb the existing roof?
A: No — the design avoids disturbing the original roof assembly or interior finishes.