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Screw-FIX Long Tail Increaser - Ø 125-150mm (25-125-MRLT)

National Flues presents the durable Screw-FIX Long Tail Increaser - Ø 125-150mm, a top-notch 316L stainless steel adaptor designed for seamless connections in chimney systems. This essential flue accessory bridges single wall flue systems with MI-FLEX flexible liners, supporting a range of fuel types including wood, oil, gas, and smokeless coal. Reliable, efficient, and safety-compliant, it is the ideal solution for quality chimney installations.
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£41.99
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At a Glance

  • High-grade 316L stainless steel construction
  • Compatible with wood, oil, gas, and smokeless coal appliances
  • Designed for secure, gas-tight transitions between flue systems
  • Compliant with Building Regulations Document J and CE/HETAS standards
  • Ideal for use with MI-FLEX flexible flue liners

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Have Questions?
Phone: 01670 206999
Email: [email protected]

The Screw-FIX Long Tail Increaser - Ø 125-150mm is a high-quality, 316-grade stainless steel adaptor designed for seamless transitions between single wall connecting flue systems and MI-FLEX flexible flue liners. Ideal for use with various fuels such as wood (with less than 20% moisture), smokeless coal, gas, and oil, this increaser supports appliance temperatures up to 600°C (T600). Compliant with Building Regulations Document J, it ensures installation must be fully enclosed within a masonry chimney.

Creating a gas-tight seal is crucial; hence, it is advisable to use fire cement, ceramic rope or tape, or high-temperature sealant. This increaser also facilitates easy provisions for maintenance and chimney sweeping, which are essential to keep your system in top shape. Always opt for competent professionals for sweeping to avoid damage to the flue system.

SKU: 25-125-MRLT

Technical Specifications
SKU25-125-MRLT
DesignationBSEN 1856-2 T600 N1 W V2 L50012 G
Material316L Stainless Steel
Colour FinishStainless Steel / NATURAL
SystemMI-FLEX Accessories MF20
FuelsWood, Oil, Gas, Smokeless coal
Temperature Rating600u00b0C
ComplianceCE / HETAS, Building Regulations Document J
Ensure the flexible flue liner is fully enclosed within a masonry chimney in compliance with Building Regulations Document J. Use fire cement, ceramic rope or tape, or a high-temperature sealant to create a gas-tight seal. Always select a competent professional for installation and annual chimney sweeping to avoid any issues. Avoid using chemical cleaners or mild steel tools on stainless steel components to ensure longevity.

The Screw-FIX Long Tail Increaser is designed to connect single wall flue systems to flexible flue liners, ensuring a smooth transition and a secure, gas-tight seal.

Yes, it is suitable for use with wood (with less than 20% moisture), smokeless coal, gas, and oil, supporting appliance temperatures up to 600°C.

To ensure a gas-tight seal, it is recommended to use fire cement, ceramic rope or tape, or high-temperature sealant.

Yes, per Building Regulations Document J, the flexible flue liner must be installed fully enclosed within a masonry chimney. Any form of timber or plasterboard boxing is not acceptable.

It’s recommended to have the chimney system cleaned and inspected at least once a year. However, for solid fuel appliances, sweeping should occur at least twice a year – at the end of the heating season and before the next heating season starts.

No, chemical cleaners and mild steel tools should not be used for sweeping stainless steel chimneys. Always opt for professional cleaning.

While it's possible for those experienced with chimney installations, it's highly recommended to hire a competent professional to ensure all components are correctly installed and comply with building regulations.
Delivery Information +

We work relentlessly to ensure you get your order fast. Estimated delivery for this product is Wednesday, April 30th. If you need faster stove or fireplace delivery please give us a call. We can often reduce longer lead times if we pay the carrier £25 for express delivery. Visit our Shipping Information page for more information.

Warranty & Returns +

All our products come with warranties. Mi-Flex offers a lifetime guarantee. Returns for damaged items are covered by insurance; non-damaged returns incur return delivery costs.

Price Match Guarantee +

We will match any price like for like on a retail basis. Give us a call if you find it cheaper and want to buy from us.

Read our review in our Screw-FIX Long Tail Increaser - Ø 125-150mm buyers guide

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