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Increasing MI-FLEX Adaptor - Ø 100-Ø 125 (20-100-MR)

National Flues presents the Increasing MI-FLEX Adaptor - Ø 100 to Ø 125, a premium accessory engineered for seamless integration between rigid single-wall flue systems and MI-FLEX flexible flue liners. Read more...
Now only £20.99
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At a Glance

  • Seamless transition from a single-wall rigid flue to a flexible MI-FLEX liner
  • Constructed from durable 316L stainless steel for long-lasting performance
  • Supports a range of fuels including wood (<20% moisture), oil, gas, and smokeless coal
  • Withstands high operating temperatures up to 600°C (T600 designation)
  • HETAS and CE approved to meet Building Regulations Document J

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At National Flues, we continuously monitor competitor prices. This ensures that we consistently offer you the best deals on all our products. Here’s how we keep your costs low:

  • Daily Price Matching: Our team adjusts prices to ensure we stay competitive.
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Price Match Guarantee: If you find the same product cheaper within 48 hours, we’ll match it and refund the difference.

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Have Questions?
Phone: 01670 206999
Email: sales@nationalflues.com

The Increasing MI-FLEX Adaptor Ø 100 to Ø 125 is a must-have accessory for your MI-FLEX 316 and 904 flexible flue liners. This robust 0.6mm 316 stainless steel adaptor is meticulously crafted to serve as a transitional joint, increasing the diameter from a single-wall connecting flue system to a flexible liner by up to 25mm. Ideal for use with appliances operating at temperatures up to 600°C (T600 designation), it supports wood with less than 20% moisture, smokeless coal, gas, and oil.

Complying with Building Regulations Document J, this adaptor must be used within a fully enclosed masonry chimney. Ensuring a secure, gas-tight seal is critical – fire cement, ceramic rope, tape, or high-temperature sealant is recommended for optimal connection integrity. Regular maintenance is essential, with HETAS registered sweeps recommended for solid fuel applications.

Sweep your chimney at least twice a year for optimal performance and longevity.

SKU: 20-100-MR

Delivery Information* +

We work relentlessly to ensure you get your order fast. Estimated delivery for this product is Friday, November 14th. This is based on current lead times. Bear in mind that it is a busy time of year. If you need a product delivered by a specific time in the next 7 days, then please give us a call on 01670 206 999. Visit our Shipping Information page for more information.

About National Flues Ltd +

We began over 30 years ago as a fireplace shop in the North East. We now supply hundreds of trade professionals and thousands of retail customers, all across the UK, every month. We are still a family owned business, lead by the MD Neil, and always try our best to deliver the best possible experience. We also price match, so give us a call if you find this cheaper and want to buy from us. Visit our about us page to read a bit more.

Technical Specifications
SKU20-100-MR
Material316L Stainless Steel
Adaptor DiameterØ 100 to Ø 125 mm
Wall Thickness0.6 mm
Operating TemperatureUp to 600°C
Fuel CompatibilityWood (<20% moisture), Oil, Gas, Smokeless Coal
StandardsHETAS / CE Approved
SystemMI-FLEX Accessories MF20
Before installing the Increasing MI-FLEX Adaptor, ensure your flue system is completely enclosed within a masonry chimney, as stipulated by Building Regulations Document J. Begin by properly preparing the surfaces for a gas-tight seal. Use high-temperature sealants such as fire cement, ceramic rope, or tape to secure joints reliably. Avoid using chemical cleaners or mild steel tools on stainless steel components. It is recommended to have the installation checked by a HETAS registered professional to ensure compliance with all safety standards. Regular maintenance, including bi-annual flue sweeps, is essential for ensuring optimal performance and longevity of the system.

This adaptor is specifically designed for use with MI-FLEX 316 and 904 flexible flue liners, ensuring seamless transitions and secure connections.

The adaptor is suitable for use with wood (<20% moisture), smokeless coal, gas, and oil, and can handle temperatures up to 600°C.

Yes, Building Regulations Document J requires that the flexible flue liner and its accessories must be installed within a fully enclosed masonry chimney.

To ensure a gas-tight seal, use fire cement, ceramic rope or tape, or high-temperature sealant during installation.

Can chemical cleaners be used for chimney maintenance?

No, chemical cleaners and mild steel tools should not be used on stainless steel chimneys. Professional chimney sweeps, preferably registered with HETAS, should be engaged for this task.

The Increasing MI-FLEX Adaptor provides a transitional increase of up to 25mm from the single wall flue to the flexible flue liner.

 

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