× National Flues
We Won't Be Beaten On Price.
Free Delivery on Orders Over £100
100% 5 Star Reviews on Trustpilot
Free Flue Design Service Available
Need Help? 01670 206999 (8am-5pm)

Single Wall to Twin Wall Increaser Ø 125 - Ø 150 (2-125-002)

National Flues proudly presents the Single Wall to Twin Wall Increaser Ø 125 - Ø 150, engineered to provide a reliable and efficient transition between single wall flue pipes and twin wall systems. Crafted from premium stainless steel and enhanced with compressed rockwool insulation, this TWPro adaptor is ideal for a range of applications including wood, gas, and oil appliances. With robust HETAS approval and CE marking, it meets the demands of modern heating systems while ensuring optimum safety. Explore optional accessories to further enhance your chimney installation and performance.
Hover to Zoom / Click for Gallery
£21.99
Give us a call if you find it cheaper and we'll try to price match.

 

Payment Options

At a Glance

  • Designed for seamless connection between single wall and twin wall systems
  • Constructed with durable 304-grade (outer) and 316-grade (inner) stainless steel, both 0.4mm thick
  • Features compressed rockwool insulation (200kg/m3) for optimal thermal efficiency
  • Tapered design increases diameter by 25mm ensuring a smooth transition
  • Fully HETAS approved and CE marked for safe, compliant installations
  • Suitable for a variety of appliances including wood stoves, gas coal effect fires, oil and gas boilers

Please Note: All dimensions refer to the internal diameter of flues. If unsure, please call 01670 206999 to ensure you choose the correct products.

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 Single Wall to Twin Wall Increaser Ø 125 - Ø 150 is the perfect solution for connecting various appliances to your TWPro Twin Wall Insulated Chimney system. Suitable for use with solid fuel and gas/oil appliances, such as woodstoves, gas coal effect fires, and oil and gas boilers, this increaser ensures a smooth and efficient transition. Constructed with 304-grade stainless steel for the outer skin and 316-grade stainless steel for the inner skin, both 0.4mm thick, this increaser guarantees durability and corrosion resistance.

The insulation is composed of compressed rockwool, achieving a density of 200kg/m3, providing exceptional thermal insulation. Fully welded parts ensure airtight connections, with a necessary clearance of 50mm from combustibles to enhance safety. This product meets rigorous industry standards with HETAS approval and CE marking, adhering to EN1856-1 T600 N1 W V2 L50040 G50 and EN1856-1 T200 W V2 L50040 O20 certifications.

Designed for easy installation, TWPro parts are secured with a locking band, ensuring reliable performance for all your chimney system needs.

SKU: 2-125-002

Technical Specifications
ModelSingle Wall to Twin Wall Increaser u00d8 125 - u00d8 150
ConstructionOuter: 304-grade Stainless Steel (0.4mm thick), Inner: 316-grade Stainless Steel (0.4mm thick)
InsulationCompressed Rockwool (200kg/m3 density)
CertificationsHETAS / CE (EN1856-1 T600 N1 W V2 L50040 G50, EN1856-1 T200 W V2 L50040 O20)
Clearance50mm from combustibles
CompatibilitySuitable for wood stoves, gas coal effect fires, oil/gas boilers
DesignTapered increment increases diameter by 25mm for optimal transition
Before commencing installation, ensure you have read the manufacturer’s guidelines thoroughly. Begin by securely fitting the locking band to join the increaser with your TWPro Twin Wall Insulated Chimney system. Maintain a clearance of 50mm from any combustible materials, such as wood or plasterboard. Use appropriate tools and follow safety procedures to guarantee an airtight connection. If installing in a challenging position, double-check that all measurements conform to the safety standards outlined in the installation manual. It is advisable to wear protective gear throughout the installation process and, if in doubt, consult a professional installer to ensure compliance with local building regulations.

The Single Wall to Twin Wall Increaser Ø 125 - Ø 150 is suitable for solid fuel and gas/oil appliances, including woodstoves, gas coal effect fires, and oil and gas boilers.

The increaser is constructed with an outer skin of 304-grade stainless steel and an inner skin of 316-grade stainless steel, both 0.4mm thick. The insulation is compressed rockwool with a density of 200kg/m3.

Yes, the product is HETAS approved and CE marked, adhering to EN1856-1 T600 N1 W V2 L50040 G50 and EN1856-1 T200 W V2 L50040 O20 certifications.

Installation involves securing the TWPro Twin Wall Insulated Chimney parts with a locking band and ensuring a 50mm clearance from any combustible materials such as wood or plasterboard.

The increaser connects single wall flue pipes or vitreous enamel pipes to twin wall systems, ensuring a smooth transition for efficient flue system performance.

A clearance of 50mm must be maintained from the outside of the flue to any combustible material such as wood or plasterboard.

The tapered design allows for a smoother transition between single wall and twin wall systems, increasing the diameter by 25mm and enhancing operational efficiency.
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 Single Wall to Twin Wall Increaser Ø 125 - Ø 150 buyers guide

Upgrade your chimney installation now and experience unparalleled performance!

Your recently viewed products:

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