Verplas 150mm to 125mm Round Duct Reducer

Description

The Verplas VKC619 is a 150mm to 125mm white uPVC round duct reducer, providing a neat, push-fit transition between 150mm and 125mm round duct runs. It is used wherever a 150mm System 150 duct run needs to step down to a 125mm connection — for example, at a fan unit with a 125mm spigot, or when transitioning from a 150mm main run to a 125mm branch. Overall dimensions are approximately 155 × 155 × 60 mm.

150mm

Inlet Diameter

125mm

Outlet Diameter

Push-Fit

Tool-Free

White uPVC

Material

60mm

Body Length

Direction: The VKC619 steps down from 150mm to 125mm. The 150mm female socket receives the male spigot of System 150 duct pipe or fittings. The 125mm male spigot inserts into System 125 female fittings. For stepping up from 125mm to 150mm, the reducer can be used in reverse.

Key Features

150mm to 125mm Transition

Provides the standard one-piece reduction between the System 150 (150mm) and System 125 (125mm) Verplas round duct ranges — no improvised adaptor or taped junction required.

White uPVC Construction

Made from white uPVC matching both System 150 and System 125 duct components for a consistent, professional appearance.

Push-Fit Both Ends

The 150mm female socket accepts System 150 male spigots, and the 125mm male spigot inserts into System 125 female connectors — both tool-free.

Compact Body

At just 60mm in body length, the reducer is compact and easy to install in ceiling voids and service spaces where transitions are often space-constrained.

System 150 & System 125 Compatible

Works with both Verplas System 150 and System 125 round duct components — connectors, bends, telescopic pipes, fans, and terminals.

Fan Spigot Adapter

Commonly used to adapt a 150mm duct run to a fan with a 125mm (5") outlet spigot, or to reduce from a 150mm main run to a 125mm branch connection.

Specifications

Verplas SKU	VKC619
Inlet Diameter	150 mm (female socket)
Outlet Diameter	125 mm (male spigot)
Body Length	~60 mm
Material	White uPVC
Overall Dimensions	155 × 155 × 60 mm (H × W × D)
System	Verplas System 150 / System 125 interface

Frequently Asked Questions

Can I use this reducer in reverse to step up from 125mm to 150mm?

The reducer can be used in reverse physically, but the push-fit seal geometry is designed for the standard direction. For a step-up transition, it is better to use the equivalent Verplas 125mm-to-150mm reducer if available, or confirm that the reverse-fit creates a satisfactory joint with your supplier.

Does reducing from 150mm to 125mm affect airflow?

Reducing the duct diameter increases air velocity and system resistance. Ensure your fan can deliver the required flow rate against the increased pressure of the smaller diameter section.

What reducer do I need to step from 200mm to 150mm?

Use the Verplas VKC436V (200mm to 150mm round reducer) for that transition.

Is there a reducer from 150mm to 100mm?

Yes — the Verplas VKC437 is the 150mm to 100mm round reducer, available separately.

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