reading can be taken with the stove lit. Two flue draught readings should be
taken, one with the stove at minimum firing rate and one at maximum firing rate.
Measurement
The flue draught test hole must be drilled in the flue pipe as close to the stove as
possible and before any flue draught stabiliser.
Minimum
The stove should be lit and allowed to warm the flue thoroughly. The air controls
can then be set so that the stove burns on a low setting. Allow the burning rate
to become steady. The flue draught reading should now be taken with the
thermostatic air intake closed and the airwash control fully open.
Maximum
The thermostatic air intake can now be opened to allow the stove to burn at
maximum rate. Give the stove some time for the burning rate to become steady,
make sure the airwash control is fully open and take a flue draught reading
immediately.
Ideally, the flue draught readings should range between 1mm wg and 2.5mm wg.
Any readings significantly outside this range may indicate the need for remedial
action.
If the draught reading is excessive then a draught stabiliser should be fitted to
achieve better fuel burning rates.
Lack of draught or downdraught should be avoided for satisfactory performance
Flue Diagnosis
Fig 3:
Chimney conditions.
6