× National Flues
We Will NOT Be Beaten on Price.
Free Delivery on Orders Over £100
5 Star Reviewed on Trustpilot
Free Flue Design Service Available
Help? 01670 206999 (8am-5pm)

Increasing MI-FLEX Adaptor - Ø 125-Ø 175

Discover the superior Increasing MI-FLEX Adaptor by National Flues – a robust and reliable stainless steel solution designed to bridge the gap between ridged single wall flue systems and MI-FLEX flexible liners. Engineered for high performance and safe operation at temperatures up to 600°C, this ada... More...
Hover to Zoom / Click for Gallery

At a Glance

  • 0.6mm 316 stainless steel construction
  • Increases flue diameter from Ø125mm to Ø175mm (50mm increase)
  • Durable, high-temperature resistance up to 600°C (T600 designation)
  • Compatible with wood (<20% moisture), oil, gas, and smokeless coal
  • BSEN 1856-2 T600, HETAS & CE compliant; Building Regulations Document J approved
Now only £66.49
Including VAT Buy with confidence. If you find this cheaper within 48 hours of checkout, we'll refund the difference.

 

Payment Options

We Won't Be Beaten On Price

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.
  • Bulk Purchasing Power: We sell a lot, so we can negotiate better rates with suppliers, passing the savings directly to you.
  • Operational Efficiency: We have streamlined processes to reduce overhead.

Price Match Guarantee: If you find the same product cheaper within 48 hours, we’ll match it and refund the difference.

Free Delivery Over £100: Orders over £100 are free delivery (call us if delivery is required outside the mainland UK).

“I saved 20% on my purchase compared to other retailers. Exceptional service!” – Jane D.

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

The Increasing MI-FLEX Adaptor - Ø125mm to Ø175mm from National Flues is a must-have for any chimney setup. This 0.6mm 316 stainless steel adaptor serves as a transitional joint that effortlessly connects a ridged single wall flue system to MI-FLEX flexible flue liners. Designed to boost performance and improve system integrity, this adaptor increases the diameter by 50mm, accommodating a variety of fuel types including wood (with moisture <20%), smokeless coal, gas, and oil.

Engineered to withstand temperatures up to 600°C (T600 designation), it ensures a gas-tight seal with the use of fire cement, ceramic rope, or high-temperature sealant. Building Regulations Document J compliance guarantees safe and effective installation within a masonry chimney. Regular maintenance, such as sweeping and inspections done by a competent person, ensure longevity and optimal performance.

SKU: 20-125-MRD

Technical Specifications
Material316L Stainless Steel
Thickness0.6mm
Diameter Conversionu00d8125mm to u00d8175mm
Temperature RatingUp to 600u00b0C (T600)
Fuel CompatibilityWood (<20% moisture), Oil, Gas, Smokeless Coal
CertificationsBSEN 1856-2 T600, HETAS, CE
SystemMI-FLEX Accessories MF20
ComplianceBuilding Regulations Document J
Install the Increasing MI-FLEX Adaptor within the confines of an existing masonry chimney. Ensure that no flex element is visible by fitting the adaptor securely inside the chimney structure. Use fire cement, ceramic rope, or a high-temperature sealant to achieve a gas-tight seal, preventing any leakage of exhaust gases. For safety, always adhere to the manufacturer’s guidelines and consult a certified installer if unsure. Regular maintenance, including routine sweeping by a HETAS registered professional, is essential to maintain peak performance and system safety.

The adaptor is made from 0.6mm 316 stainless steel, providing high durability and resistance to corrosion under extreme temperatures.

Yes, the adaptor meets Building Regulations Document J requirements, ensuring it can be safely enclosed within a masonry chimney.

The adaptor is suitable for use with wood (with less than 20% moisture content), smokeless coal, gas, and oil.

The adaptor should be installed within the confines of an existing masonry chimney, ensuring no flex is visible. Use fire cement, ceramic rope, or high-temperature sealant to achieve a gas-tight seal.

Regular sweeping and maintenance are essential. It is recommended to sweep chimneys serving solid fuel appliances twice a year, and at least once annually for other systems.

No, chemical cleaners and mild steel tools should not be used. Use appropriate methods and tools to avoid damaging the stainless steel components.

You can find a list of HETAS registered sweeps at www.hetas.co.uk, ensuring qualified professionals conduct the chimney sweeping.
Delivery Information +

We work relentlessly to ensure you get your order fast. Estimated delivery for this product is Thursday, April 3rd. 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. If you find it cheaper within 48 hours, we'll refund the difference.

Compatible and other products that may be of interest...

Read our buyers guide for this Increasing MI-FLEX Adaptor - Ø 125-Ø 175

National Flues Ltd Verdict

The Increasing MI-FLEX Adaptor is an essential component for any chimney system installation, ensuring a seamless transition between different flue sizes. At National Flues, we take pride in delivering high-quality products at unbeatable prices, with reliable nationwide delivery and secure online payments for both retail and trade customers.

The Increasing MI-FLEX Adaptor is used to connect ridged single wall flue systems to MI-FLEX flexible flue liners, ensuring a seamless and gas-tight transition between different flue sizes.

National Flues is a premier supplier of fireplaces and flues across the UK, known for unbeatable prices, reliable delivery services, and secure transactions for both retail and trade customers.

 

Our Rating Image

Secure your Increasing MI-FLEX Adaptor now for unmatched quality and performance.

Your recently viewed products:

Multiple Payment Options- including Klarna, Clearpay, Mastercard, Visa and Paypal
Free Design Service