Product Description

125mm VIT-Smooth Adjustable Flue Pipe – 500mm

Model: 67-125-020

The 125mm VIT-Smooth adjustable flue pipe provides a flexible solution where a standard fixed pipe does not match the required installation length. The 500mm one-part pipe slides into the female end of a compatible VIT-Smooth pipe or fitting and provides up to approximately 400mm of usable length.

Once the installer achieves the required overlap and overall length, the supplied clamp secures the adjustable section in position. Therefore, it can help create a neat, accurately measured connection without relying on several short fixed-pipe sections.

The pipe is made from 1.2mm zero-carbon steel and finished with powder vitreous enamel. Its smooth matt black appearance coordinates with compatible VIT-Smooth stove pipe and many modern or traditional heating appliances.

125mm Adjustable Flue Pipe Features

• 125mm (5-inch) nominal flue diameter
• 500mm nominal one-part adjustable pipe
• Up to approximately 400mm usable length
• Slides into the female end of a compatible pipe or fitting
• Allows precise adjustment during installation
• Supplied with a securing clamp
• Manufacturer model number: 67-125-020
• Made from 1.2mm zero-carbon steel
• Approximately 0.2mm powder vitreous enamel coating
• Approximately 1.4mm total thickness, including enamel
• Internal and external enamel finish
• Heat-resistant matt black colour
• Suitable for compatible gas, oil and solid-fuel appliances
• Maximum continuous operating temperature: 600°C
• Product designation: EN 1856-2 T600 N1 Vm L80120 G375
• Minimum declared distance from combustible materials: 375mm
• 12-year warranty, subject to the manufacturer’s terms

Technical Specification

• Product type: One-part adjustable connecting-flue pipe
• Nominal diameter: 125mm (5 inches)
• Nominal length: 500mm
• Usable length: Up to approximately 400mm
• Adjustment method: Slides into a compatible female connection
• Securing method: Supplied locking clamp
• Material: Zero-carbon steel
• Steel thickness: 1.2mm
• Enamel thickness: Approximately 0.2mm
• Total thickness: Approximately 1.4mm
• Coating: Powder vitreous enamel
• Colour: Matt black
• Temperature classification: T600
• Product standard: EN 1856-2
• Distance from combustibles: 375mm
• Warranty: 12 years, subject to terms
• Model: 67-125-020

How Does the Adjustable Flue Pipe Work?

The adjustable end slides inside the female end of an existing compatible pipe or fitting. The installer can alter the amount of overlap until the assembly reaches the required length.

The component provides up to approximately 400mm of usable length rather than adding the full 500mm to the completed system. Always allow for the required overlap and connection depth when measuring the flue route.

Once correctly positioned, the supplied clamp secures the overlapping sections. The clamp must fit and tighten in accordance with the manufacturer’s instructions so the assembly cannot move during normal operation, maintenance or sweeping.

When Should You Use an Adjustable Flue Pipe?

This pipe may help when the distance between two fixed components does not correspond with a standard flue-pipe length. For example, it can provide the final adjustment between a fixed stove-pipe section and a suitable adaptor or chimney connection.

It may also simplify future dismantling for maintenance when the complete design allows it. However, the adjustable pipe must remain accessible for inspection and must not extend through a wall, ceiling or concealed space.

One-Part Adjustable Pipe Versus Fixed Pipe

A fixed pipe provides one predetermined installed length. In contrast, this adjustable section changes length by sliding farther into or out of its compatible receiving component.

The overlapping design means the installer can fine-tune the completed route without cutting a standard pipe unnecessarily. Nevertheless, the system must retain sufficient overlap and the supplied clamp must remain correctly fitted.

Why Choose VIT-Smooth?

VIT-Smooth combines robust steel with a smooth vitreous enamel finish. Consequently, it provides an attractive option for visible single-wall connecting flues.

The internal and external enamel coating also helps protect the steel against heat, combustion gases and corrosive deposits. Its matt black finish coordinates with many wood-burning and multifuel stoves.

Suitable Applications

• Compatible wood-burning stoves
• Compatible multifuel stoves
• Suitable gas heating appliances
• Suitable oil-fired appliances
• 125mm VIT-Smooth connecting-flue systems
• Visible single-wall stove-pipe installations
• Fine adjustment between fixed flue components
• Connections leading towards a suitable chimney system

Measuring Before Ordering

Measure the distance between the relevant connection points and account for every joint, adaptor, bend and required overlap. Do not assume that a 500mm adjustable pipe adds exactly 500mm to the completed route.

This model provides up to approximately 400mm of usable length. The installer must also retain the minimum overlap required by the manufacturer and ensure the supplied clamp can secure the assembly correctly.

If the required length falls outside the pipe’s usable adjustment, choose a different combination of approved fixed and adjustable components.

Can the Adjustable Pipe Be Cut?

The pipe can be shortened when necessary, but the manufacturer does not generally recommend cutting it. Altering the component may affect its adjustment, overlap and ability to connect correctly.

If cutting is unavoidable, a competent installer must confirm that the remaining pipe still provides the required engagement and works with the supplied clamp. They must also remove sharp edges without distorting the pipe.

Apply suitable high-temperature protective paint to every exposed steel edge. Otherwise, moisture may reach the uncoated metal and cause corrosion.

Installation Direction

Install the flue arrangement so the smaller or male ends point downwards towards the appliance. This orientation helps keep condensate and combustion deposits inside the flue system.

The installer must also check that the adjustable pipe enters the correct female connection. Do not reverse the system or force together components with incompatible joint profiles.

Using the Supplied Clamp

The supplied clamp secures the adjustable pipe after the installer sets the required length. Position and tighten it according to the current VIT-Smooth instructions.

The clamp does not compensate for inadequate overlap, damaged pipe or incompatible components. Before completing the installation, check that the assembly remains correctly aligned and cannot slide, rotate or separate.

Jointing and Sealing

Compatible VIT-Smooth components use close-fitting connections. Jointing compound is not automatically required at every correctly assembled joint.

However, sealing requirements can vary according to the particular connection and complete chimney design. Only use suitable fire cement, high-temperature sealant or another jointing product when the appliance and flue manufacturers permit it.

Do not use sealant to compensate for poor engagement or to hold an insecure adjustable section together. The parts must fit correctly, retain adequate overlap and use the supplied clamp.

Installation and Safety Information

Use VIT-Smooth only as a single-wall connecting flue between a compatible appliance and a suitable chimney, flexible liner or insulated twin-wall system. Never use this pipe to pass through a wall, ceiling, roof or concealed void.

Maintain at least the declared 375mm distance from combustible materials. These may include timber, furniture, combustible wall finishes and some plasterboard constructions. Follow any greater clearance stated by the appliance manufacturer.

Keep the adjustable joint accessible for inspection. Do not conceal the sliding connection or position the locking clamp where it cannot be checked and maintained.

A competent installer should design and fit the complete system. For solid-fuel work, use a suitably qualified installer, such as a HETAS-registered installer, or notify Building Control where required.

Finally, follow the appliance instructions, current VIT-Smooth guidance and applicable Building Regulations. The appliance manufacturer’s instructions determine the permitted flue diameter, route and connection method.

Inspection and Maintenance

The chimney system must provide suitable access for inspection and sweeping. During routine maintenance, check the adjustable joint, overlap and securing clamp for movement, corrosion or damage.

A competent person should inspect and clean the chimney regularly. The required frequency depends on the appliance, fuel, chimney condition and level of use.

Use suitable cleaning equipment that will not damage the vitreous enamel. Replace any component that shows significant corrosion, distortion, enamel damage or an insecure joint.

Product Guide

• Download the VIT-Smooth brochure

Why Buy from SNH Tradecentre?

• Competitive prices: We aim to offer excellent value across our flue and chimney range.
• Helpful advice: Our team can help you compare adjustable and fixed pipe lengths.
• Genuine products: Order from an established plumbing and heating merchant.
• Collection available: Collect eligible in-stock products from our Birchington trade counter.
• UK delivery: Choose from the available delivery services at checkout.
• Trade and public welcome: We supply installers, homeowners, landlords and property professionals.

Need help selecting the correct adjustable pipe? Call SNH Tradecentre on 01843 842727 before ordering. If possible, have the appliance model, flue diameter and required installed length ready.

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Frequently Asked Questions

What diameter is this adjustable flue pipe?

It has a nominal diameter of 125mm, equivalent to approximately five inches. It is designed for compatible 125mm VIT-Smooth components.

What is the usable length?

The 500mm one-part pipe provides up to approximately 400mm of usable length. The exact installed length depends on the overlap required within the adjoining component.

Why is the usable length shorter than 500mm?

Part of the adjustable pipe must remain inside the compatible female connection. Therefore, the full physical length cannot be added to the completed flue route.

How is the pipe adjusted?

It slides into the female end of a compatible VIT-Smooth pipe or fitting. The installer sets the required overlap and then secures the assembly with the supplied clamp.

Is a securing clamp included?

Yes. The product comes with a clamp designed to secure the adjustable sections after the installer achieves the required length.

Can I use it as a telescopic pipe between any two components?

No. It must enter a compatible female connection and retain the required overlap. Confirm the complete joint arrangement before ordering.

Can the adjustable pipe be cut?

It can be shortened, but cutting is not generally recommended. If alteration is necessary, a competent installer must preserve the correct connection and protect all exposed steel with suitable high-temperature paint.

Can I connect it directly to every 125mm stove?

Not necessarily. Stove outlets can have different dimensions and joint profiles. A suitable stove adaptor may be required.

Can I use it with a wood-burning stove?

It may suit a compatible wood-burning or multifuel stove. However, the appliance manufacturer must permit the 125mm flue diameter and proposed single-wall arrangement.

Which way up should the pipe be installed?

The complete system should have its smaller or male ends pointing downwards towards the appliance. This helps keep condensate and deposits inside the flue.

What is the maximum operating temperature?

The product carries a T600 classification. Therefore, its maximum continuous operating temperature is 600°C. Always observe any lower limit specified by the appliance manufacturer.

Can this pipe pass through a wall or ceiling?

No. This is a single-wall connecting-flue component. It must not pass through walls, ceilings, roofs or concealed spaces.

How far must it be from combustible materials?

The product designation declares a minimum distance of 375mm from combustible materials. However, the installer must observe any greater clearance required by the appliance or current regulations.

Does the adjustable joint require sealant?

Not automatically. Compatible components must first engage correctly and retain the required overlap. Only use an approved jointing material when the current appliance and flue instructions permit it.

Who should install this adjustable flue pipe?

A competent installer should fit it as part of a properly designed chimney system. For solid-fuel installations, consider using a HETAS-registered installer or arranging Building Control notification where required.

Manufacturers may update specifications and installation guidance. Therefore, check the latest VIT-Smooth literature and confirm the required overlap and usable length before ordering.