Flueet — Chimney flue sizing, draught and liner choice | flueet.com
A sealed stove should show 4-6 Pa at the outlet and an open fire 5-10 Pa; a reading below that range has a cause, and the causes are findable.
Draught is the negative pressure a chimney develops, and it is measured, not guessed. A manometer or digital draught gauge connected at the appliance outlet gives the reading, taken with the fire established and the flue warm rather than on a cold chimney.
Start at the top. A terminal that sits too low — under the 1 m requirement when more than 2.3 m from a boundary, or under 2.1 m when closer — can leave the pot in disturbed air, and no adjustment at the stove will fix that.
On narrow screens, swipe or scroll the plate sideways.
Then check the bore. A flue smaller than the appliance outlet restricts flow, and so does a run with too many bends or a liner choked with soot. If the chimney has not been swept within its interval — twice a year on wood, once on smokeless coal — book the sweep before blaming the design.
Look at the fuel. Logs above 20% moisture burn cool, and a cool flue is a weak flue: the gases lose buoyancy before they reach the terminal. Modern appliances are designed around fuel at 20% moisture or less.
Finally, consider the room. A sealed stove still needs combustion air, and a very airtight room starves the fire no matter how well the chimney is sized. If the reading stays below range after these checks, the sizing guide and the liner guide set out the hardware side of the fix.
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