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Top Insert Sleeve - Ø 125 (20-125-PS)

At National Flues, our Top Insert Sleeve - Ø 125 is meticulously engineered to provide secure and lasting chimney support. As part of the distinguished MI-FLEX Accessories MF20 range, this product excels in ensuring chimney system integrity and safety. Read more...
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At a Glance

  • Made from robust 316L stainless steel
  • Natural / Stainless Steel finish for longevity
  • Withstands temperatures up to 600°C (T600)
  • Certified to HETAS and CE standards
  • Compatible with wood (under 20% moisture), oil, gas, and smokeless coal
  • Designed for use with MI-FLEX Accessories MF20 systems
  • Essential for supporting the weight of flexible flue liners
  • Works in tandem with Top Plate and Top Clamp

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: sales@nationalflues.com

The Top Insert Sleeve - Ø 125 is an essential component for anyone installing or maintaining a chimney system using MI-FLEX 316 and 904 flexible flue liners. This expertly designed accessory slides seamlessly into the flexible chimney liner at the top of your installation. Used in conjunction with a Top Plate and Top Clamp, it ensures that the flue liner's weight is securely supported without compromising its integrity.

This robust sleeve is suitable for a range of fuel types including wood with less than 20% moisture, smokeless coal, gas, and oil, and can withstand temperatures up to 600°C (T600). According to Building Regulations Document J, a flexible flue liner must be entirely enclosed within a masonry chimney, making the Top Insert Sleeve an indispensable part of your setup. Proper maintenance is crucial; sweeping and inspection should be conducted at least annually by a qualified professional to ensure longevity and performance.

SKU: 20-125-PS

Delivery Information* +

We work relentlessly to ensure you get your order fast. Estimated delivery for this product is Monday, November 17th. 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
Material316L Stainless Steel
Colour FinishNatural / Stainless Steel
Temperature RatingUp to 600°C (T600)
ApprovalsHETAS / CE
Compatible FuelsWood (<20% moisture), Oil, Gas, Smokeless Coal
SystemMI-FLEX Accessories MF20
DimensionsØ 125mm
DesignationBSEN 1856-2 T600 N1 W V2 L50012 G
The Top Insert Sleeve - Ø 125 is designed for easy integration into your chimney system. Begin by ensuring that the flexible flue liner is correctly prepared and positioned within your masonry chimney. Slide the insert sleeve into place at the top of the liner, then secure it using the appropriate Top Plate and Top Clamp. It is essential that the chimney liner remains completely enclosed in a masonry structure in line with Building Regulations Document J. Regular annual sweeping and inspections by qualified professionals are recommended to maintain performance and extend the life of both the flue liner and the sleeve. Avoid using chemical cleaners or mild steel tools during maintenance to prevent damage to the stainless steel surfaces.

The Top Insert Sleeve - Ø 125 is used to support the weight of a flexible flue liner at the top of a chimney stack, ensuring the integrity of the installation.

Yes, this insert sleeve is suitable for wood with less than 20% moisture, smokeless coal, gas, and oil.

The Top Insert Sleeve can withstand temperatures up to 600°C, meeting the T600 designation.

Yes, Building Regulations Document J requires that the flue liner be completely enclosed inside a masonry chimney. A non-masonry enclosure like timber or plasterboard is not acceptable.

The chimney system should be inspected and swept at least once a year. For chimneys serving solid fuel appliances, it's recommended to sweep twice a year – at the end of the heating season and at the start of the next one.

No, chemical cleaners and mild steel tools should never be used to sweep stainless steel chimneys. Always consult a professional chimney sweep.

The Top Insert Sleeve should be used alongside a Top Plate and Top Clamp to ensure the flue liner is securely supported.

 

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