Olyflow Heavy Duty TPO RetroDrain

The HDTPO3A, HDTPO4A, HDTPO5A, and HDTPO6A models are Hercules series TPO-Flange RetroDrains by OMG, designed for retrofit roof drain projects under TPO membrane systems. They feature a one-piece spun aluminum body, a TPO-coated flange engineered for direct membrane welding, a watertight U-Flow mechanical seal to connect to existing PVC or cast iron piping, and cast aluminum strainer dome and clamping components for durability in harsh environments. These drains allow rooftop drains to be upgraded without removing existing drain fixtures.

Key Features

• TPO-coated flange suited for direct hot-air welding under TPO roof membrane
• watertight U-Flow mechanical seal to existing leader pipes (PVC or cast iron)
• large 17.5-inch flange with depressed sump area to help collect water and allow proper flashing detail
• cast aluminum strainer dome and cast aluminum clamping ring for long-term corrosion resistance
• one-piece spun aluminum body with 12-inch stem to bypass existing drain body

• item numbers: HDTPO3A (3-inch), HDTPO4A (4-inch), HDTPO5A (5-inch), HDTPO6A (6-inch)
• drain body thickness: 11 gauge (0.125-inch) spun aluminum
• flange diameter: 17.5-inches with depressed sump area
• stem length: 12-inches
• strainer dome: cast aluminum
• clamp ring: cast aluminum (applies for non-coated type; TPO coated flange generally without separate clamp ring)
• seal: U-Flow watertight mechanical seal (installation requires U-Flow tool)
• packaging quantity: 1 per box
• dimensional weight: 27 lbs each

• Remove the old drain components (dome, clamping ring, flange) and clean the roof membrane and insulation around the drain opening.
• Cut the TPO membrane flush around the opening as per standards; ensure substrate or deck is clean and level under the flange.
• Insert U-Flow seal at stem end; adjust or trim stem if necessary to match existing leader pipe depth.
• Set the RetroDrain in place so the flange seats properly; weld the TPO membrane flange to the membrane using hot-air tools per membrane manufacturer instructions.
• Tighten U-Flow mechanical seal screws evenly using required tool until seal is watertight.
• Install the cast aluminum strainer dome and secure with fasteners; verify dome is aligned and seated properly.

Q: What drain sizes are available for the TPO-flange Hercules RetroDrain line?
A: Sizes are 3-inch, 4-inch, 5-inch, and 6-inch (SKUs HDTPO3A through HDTPO6A).

Q: What is the purpose of the TPO-coated flange?
A: The TPO-coated flange allows the flange to be directly hot-air welded to the TPO roofing membrane for a secure, watertight membrane interface.

Q: What type of piping can the U-Flow seal connect to?
A: It connects to existing PVC or cast iron leader pipes.

Q: How thick is the body of these retrodrains?
A: The body is 11 gauge, which equals about 0.125-inch thickness of spun aluminum.

Q: What is the weight of one unit?
A: The dimensional weight is about 27 lbs each.