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125mm (5 Inch) Flue Liner - MI-Flex Gas FLEX - Installation Packs & Accessories

Upgrade your fireplace with the 125mm (5 inch) flue liner collection from MI-Flex Gas FLEX. Whether you need a complete installation pack, fixings, terminals, or accessories, we've got you covered. Our products are designed for efficiency, durability, and easy installation, ensuring a safe and reliable flue system for your home.
Upgrade your fireplace with the 125mm (5 inch) flue liner collection from MI-Flex Gas FLEX. Whether you need a complete installation pack, fixings, terminals, or accessories, we've got you covered. Our products are designed for efficiency, durability, and easy installation, ensuring a safe and reliable flue system for your home.


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The best selling flue liner in the UK. Suitable for gas, oil, and approved solid fuels. Call our advisers on 01670 206 999 if you need any help choosing.

£1.88 £486.99
Showing 18 of 26 items
Triplelock - Installer Pack B (Clamp, GC1) - Ø 125

Triplelock - Installer Pack B (Clamp, GC1) - Ø 125

34-125-PB
£11.99 (including VAT)
In stock
Triplelock - Installer Pack C (Clamp, GC1, Nose Cone) - Ø 125

Triplelock - Installer Pack C (Clamp, GC1, Nose Cone) - Ø 125

34-125-PC
£16.99 (including VAT)
In stock
125mm (5 inch) Flue Liner 316L for Gas and Oil  (316L Grade)

125mm (5 inch) Flue Liner 316L for Gas and Oil (316L Grade)

4Z-125-1
£10.99 (including VAT)
In stock
125mm (5 inch) Flue Liner 316L for Gas and Oil 44m Coil

125mm (5 inch) Flue Liner 316L for Gas and Oil 44m Coil

4Z-125-44
from £486.99 (including VAT)
In stock
Nose Cone - Ø 125

Nose Cone - Ø 125

20-125-NC
£5.99 (including VAT)
In stock
Triplelock - Flue Adaptor - Ø 125

Triplelock - Flue Adaptor - Ø 125

34-125-A
£17.99 (including VAT)
In stock
Triplelock - GC1 Gas Terminal - Ø 125

Triplelock - GC1 Gas Terminal - Ø 125

34-125-C
£7.99 (including VAT)
In stock
Triplelock - Debris Plate (Spring Fix) - Ø 125

Triplelock - Debris Plate (Spring Fix) - Ø 125

34-125-DP
£27.99 (including VAT)
In stock
Triplelock - Flue Bug - Ø 125

Triplelock - Flue Bug - Ø 125

34-125-FB
£25.99 (including VAT)
In stock
Triplelock - Oil Cowl, Chinamans Hat - Ø 125

Triplelock - Oil Cowl, Chinamans Hat - Ø 125

34-125-O
£23.99 (including VAT)
In stock
Triplelock - Clamp Plate (2 pc.) - Ø 125

Triplelock - Clamp Plate (2 pc.) - Ø 125

34-125-P
£4.99 (including VAT)
In stock
Triplelock - Pot Hanging Cowl, Terracotta - Ø 125

Triplelock - Pot Hanging Cowl, Terracotta - Ø 125

34-125-PHCMT
£42.99 (including VAT)
In stock
125mm (5 inch) Standard Flue Box  Flue Box

125mm (5 inch) Standard Flue Box Flue Box

8-SFB
£161.99 (including VAT)
In stock
125mm (5 inch) Sheffield Pattern   Flue Box

125mm (5 inch) Sheffield Pattern Flue Box

8-SHEF
£108.99 (including VAT)
In stock
125mm (5 inch) VISA Flue Gas Collector   Flue Box

125mm (5 inch) VISA Flue Gas Collector Flue Box

8-VISA-SF
£76.99 (including VAT)
In stock
125mm (5 inch) VMF Flue Box SS  Flue Box

125mm (5 inch) VMF Flue Box SS Flue Box

8-VMFS
£80.99 (including VAT)
In stock
Debris Collar with Jubilee Connector - Ø 125

Debris Collar with Jubilee Connector - Ø 125

94-COLLAR-J-125
£14.99 (including VAT)
In stock
Register Plate (F) - 900x495, no access hole - Ø 125 & 150

Register Plate (F) - 900x495, no access hole - Ø 125 & 150

94-REG-F
£30.99 (including VAT)
In stock
Your 125MM (5 INCH) Questions Answered

What are the advantages of using a 125mm (5 inch) flue liner? -

A 125mm (5 inch) flue liner improves the draft, enhances appliance efficiency, and provides better protection for the chimney structure.

Is the 316L grade stainless steel flue liner suitable for gas and oil applications? +

Do you offer installation assistance for your flue liners? +

Can I use your flue liners for a wood-burning fireplace? +

Do you provide custom lengths for flue liners? +

Are your flue liners compliant with building regulations? +

How do I maintain and clean a 125mm (5 inch) flue liner? +

Can I use your flue liners for a multi-fuel stove? +

The 125mm (5 inch) flue liners by MI-Flex Gas FLEX offer superior quality and performance for gas and oil applications. Constructed from 316L grade stainless steel, these liners provide excellent corrosion resistance and longevity. Choose from individual liners or economical 44m coil options to suit your specific requirements. Our installation packs come with all the necessary components for a successful setup, while our range of fixings, terminals, accessories, flue boxes, and register plates offer complete customization possibilities for your flue system.
Why Buy 125MM (5 INCH) Products
The 125mm (5 inch) flue liner is ideal for residential and commercial gas and oil heating systems. It is suitable for both new installations and upgrades, ensuring proper venting and compliance with building regulations. Our products cater to a range of appliances, including boilers, stoves, and more. The versatility and durability of our flue liners make them a popular choice among installers and homeowners looking to enhance the safety and efficiency of their heating setups.

Trusted By Trade Professionals

Our 125MM (5 INCH) products and services are trusted by hundreds of professionals nationwide. We're committed to providing quality and reliability that meets the high standards of our customers.

Dedicated Support

Experience our unparalleled customer service and support when you buy 125MM (5 INCH) from National Flues. Our team is here to assist you every step of the way, ensuring your needs are met with expertise and care.