Installation Pack No. 4, Pot replacement kit with 100mm to 125mm MR flex adaptor


MF20 MI-FLEX accessories is a family of installation fitting that have been perfectly designed for use with MI-FLEX 316 and 904 flexible flue liners. When fitted in conjunction together It will make a full system chimney.



Theses items are to used in conjunction with MI-FLEX multi fuel flexible flue liner. Building Regulations Document J requires that a flexible flue liner can only be installed completely enclosed inside a masonry chimney. A non masonry enclosure such as timber or plasterboard boxing in is not acceptable. All items are suitable for use on appliances up to 600°C (T600 designation). Suitable for use on Wood <20% moisture, Smokeless coal, Gas and oil.

Installation kits
Installation kits are a complete package designed to give you all you need to install a flue liner in a specific scenario. MI-FLEX not included.

Specific Application
Use this pack when you want to remove the existing chimney pot – and then replace it when the flue liner is installed. You will probably need to install a cowl or terminal for your chimney to offer some weather and bird protection.
1 x Top Plate – Ø 125mm
1 x Top Clamp – Ø 125mm
1 x Nose Cone – Ø 125mm
1 x Increasing Adaptor to Black Pipe or Single Wall Flue – Ø 100mm SW to Ø 125mm Flex
1 x Chimney Notice Plate

The chimney system must be designed to allow for easy provision for sweeping and maintenance. Sweeping must be carried out by competent person. On solid fuel applications a list of HETAS registered sweeps can be found at under no circumstances should chemical cleaners or mild steel tools be used to sweep stainless steel chimneys. Cleaning and inspection of the chimney system should be carried out at least once a year, along with maintenance of the appliance, but it is recommended that chimneys serving solid fuel appliances be swept at least twice a year, at the end of the heating season to remove any deposits, which may have built up during the season, and at the start of the next heating season to check for any blockages or deposits. I.e. birds nets.

Product Details

SKU 20-125-P504
Item Installation Pack No 504 – Ø 100-Ø 125
Designation: BSEN 1856-2 T600 N1 W V2 L50012 G
System: MI-FLEX Accessories MF20
Material: 316L
Colour Finish: Natural / Stainless Steel
Fuels: Wood, Oil, Gas, Smokeless coal
Approvals: HETAS / CE