Extend the flue run on your Ariston condensing boiler with the genuine Ariston Coaxial Extension (part number 3318077), a 1000mm length of 60/100mm coaxial pipe designed to lengthen either the horizontal or vertical flue system without breaking the balanced-flue seal. Built to the same concentric twin-wall design as the boiler's original flue kit, it carries combustion air in through the outer 100mm sleeve while exhaust gases vent safely through the inner 60mm pipe, keeping the whole run fully sealed and weatherproof from boiler to terminal.
This extension is a core component of Ariston's 60/100 flue accessory range, used to reach further wall or roof terminal positions on both horizontal Type 1/Type 2 coaxial kits and vertical Type 3 systems routed through a pitched roof. It slots together with Ariston's push-fit coaxial joints, so no cutting, sealant or extra fixings are needed to join it into the existing run.
60/100mm
Coaxial Diameter
Gas Safe
Install Requirement
Gas Safe Installation Required
This flue extension forms part of a balanced flue system on a gas-fired appliance and must only be fitted by a Gas Safe registered engineer. The completed flue run must meet the boiler manufacturer's maximum permitted flue length and terminal clearance requirements before commissioning.
Concentric Twin-Wall Design
Combustion air is drawn in through the outer pipe while exhaust gases vent through the inner pipe, keeping the balanced flue system sealed along its full length.
Simple Push-Fit Jointing
Connects to Ariston coaxial flue components using a push-fit joint, allowing the flue run to be extended without cutting, gluing or additional brackets.
1000mm Extension Length
Adds a full metre to the flue run, making it easier to reach a suitable wall or roof terminal position on installations where the standard kit falls short.
60/100mm Coaxial Sizing
Matches the 60/100mm diameter used across Ariston's core condensing boiler range, keeping flue resistance and terminal clearances consistent with the original kit.
Horizontal and Vertical Use
Suitable for extending both horizontal balanced-flue kits and vertical roof-terminated coaxial systems on compatible Ariston boilers.
Weatherproof White Finish
Finished in white to match Ariston's standard coaxial flue components for a neat, consistent appearance on exposed external runs.
Check Boiler Model and Flue Type First
This extension is designed for Ariston's 60/100mm coaxial flue range and is not interchangeable with the 80/125mm or twin 80mm flue systems used on some other Ariston models. Always confirm the flue diameter fitted to your specific boiler before ordering, and check the boiler's maximum flue length allowance to ensure this extension does not exceed it when combined with other flue components already installed.
General
Product Type
Coaxial Flue Extension
Flue System
Diameter
60/100mm (coaxial)
System Type
Balanced flue / room-sealed
Suitable Orientation
Horizontal or vertical
Compatibility
Compatible Flue Range
Ariston 60/100mm coaxial flue accessories
Typical Boiler Ranges
Genus, Clas, E-Combi, E-System, Microgenus HE (60/100 flue models)
Installation
Must be fitted by a Gas Safe registered engineer
Works With Horizontal and Vertical Systems
The same 3318077 extension piece is used to lengthen horizontal coaxial flue kits and vertical roof-terminated systems, and pairs with components such as the Vertical Starter, Vertical Flue, 90°/45° coaxial elbows, and flashing base caps in Ariston's 60/100 accessory range.
Which Ariston boilers is the 3318077 extension compatible with?
It is designed for Ariston condensing boilers fitted with the 60/100mm coaxial flue system, including models across the Genus, Clas, E-Combi, E-System and Microgenus HE ranges. Always check your specific boiler's installation manual to confirm it uses the 60/100mm coaxial flue before ordering.
Can this extension be used on a vertical flue run?
Yes. The 3318077 extension is used on both horizontal coaxial kits and vertical roof-terminated systems, where it is combined with components such as the vertical starter and vertical flue terminal.
How does it connect to the existing flue?
It uses a push-fit coaxial joint that connects directly to other Ariston 60/100mm flue components, so no cutting or sealant is required. Installation should still only be carried out by a Gas Safe registered engineer.
Is there a shorter or longer version of this extension?
Yes. Ariston's 60/100mm coaxial range also includes a 500mm extension and a 2000mm extension for the same flue system, allowing the run to be extended in different increments depending on the installation.
Does adding this extension affect the maximum flue length for my boiler?
Yes, every extension added to a flue run counts towards the boiler's maximum permitted flue length. Check your boiler's installation manual for the maximum allowance before adding this or any other extension.
