Use the wizard to determine the required size,
or if you prefer you can refer to the table below.
| Flue Sizing Wizard |
75mm |
100mm |
125mm |
150mm |
|
| Gas Central Heating Boiler (Wall hung/Freestanding) |
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| Input up to 25kW | • |
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| Input 25kW-40kW | • |
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| Input 40kW-60kW | • |
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| Gas Fires -"Radiant" to BS 7977-1 | • |
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| Gas Fires -"Inset" to BS 7977-1 | •* |
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| Gas Fires -"Backboiler" to BS 7977-2 | • |
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| Gas Water Heaters - Input up to 25kW | • |
• |
||
| Gas Water Heaters - Input 25kW -55kW | • |
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| Gas Water Heaters - Input 55kW -60kW | • |
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| Gas Stove/Cooker - (AGA/Rayburn/Stanley etc.) | • |
• |
• |
|
| Gas Flue Blocks - Connection IN | • |
• |
||
| Gas Flue Blocks - Connection OUT | • |
|||
| Gas Warm Air Unit | ||||
| Input up to 18kW | • |
|||
| Input 18kW-35kW | • |
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| Input 35kW-60kW | • |
*When the fire has been tested and relaxed to 125° the appliance manufacturer should be consulted.
Flue size selection
B Vent is available in 75, 100, 125 and 150mm internal diameters.
The flue size must be as recommended by the appliance manufacturer and must not be reduced, and never smaller than the appliance spigot.
This information is provided as a guide only, and for exact flue sizing recommendations, refer to appliance manufacturer's installation instructions and design guide.
