FloPlast Overflow Pipe – OS01 21.5mm

FloPlast Overflow Pipe OS01 is the standard small bore plastic pipe for cistern overflows, warning pipes and boiler condensate. It comes in 21.5mm, 3m lengths, and joins with Solvent Weld fittings.

What FloPlast Overflow Pipe OS01 is used for

Run it from a loft tank or WC cistern overflow to somewhere outside where a drip will be noticed. That way a stuck fill valve shows up quickly instead of flooding a ceiling. It is also used to carry condensate from a boiler to a drain.

Cut with a pipe slice or fine saw, deburr, and cement each joint with solvent cement. Keep a continuous fall from start to finish. Clip at close spacing, because thin pipe sags between fixings.

Outside, condensate pipe can freeze in a hard winter, so keep runs short and falling well, and consider a larger pipe where the boiler maker recommends it.

Buying overflow pipe in Glasgow

Bends, couplers and tank connectors are in the Flexible range. Plumb Parts sells it at 555 South Street, Glasgow G14 0QX, open Mon-Fri 8am-5pm and Sat-Sun 8am-1pm, and online too.

Specification

• Brand: FloPlast
• Range: 21.5mm Overflow Waste
• Maker code: OS01
• Material: PVC-U
• Connection: Solvent Weld fittings
• Sizes: 21.5mm x 3m
• Max temperature: 76°C continuous; up to 100°C for under 2 minutes
• Suitable for: Cistern overflows, warning pipes and condensate runs

Common Questions

What is 21.5mm overflow pipe used for?

Overflows and warning pipes from cisterns and tanks, and condensate runs from boilers. It is not meant for appliance waste.

How are lengths of OS01 joined?

Use the matching FloPlast overflow fittings, glued with solvent cement. A straight coupler joins two lengths in line.

What temperature can overflow pipe take?

FloPlast’s tech sheet gives 76°C for continuous flow. Short discharges up to 100°C are allowed if they last under two minutes.

Datasheets

• FloPlast Overflow System Tech Sheet (PDF)