Zanussi GC 20 M Instructions For The Use And Care page 18

Adjustments
Adjusting the primary air
Light the burners and check the flame. If
the primary air needs to be adjusted, set
the sliding sheet-iron ring to be found at
the entrance of the burner's Venturi tube.
By adjusting this ring it is possible to
obtain a steady flame with a correct air-
gas mixture (see Fig. 15 a/b/c).
Adjusting the minimum flame
setting
Worktop burners
Turn the gas tap to minimum, remove the
control knob and with a screwdriver turn
the adjusting screw, which is inside the
gas tap shaft, until a small and steady
flame is obtained. Check stability of flame
by quickly turning the tap from max. to
min., re-adjusting the flame if necessary.
Attention: If the cooker is adjusted for
Methane gas, to convert it to Liquid gas
it will suffice to screw completely in the
minimum adjustment screw, after
changing the main jets.
Oven burner
After keeping the oven in operation for
about 10 minutes on the max. setting
with the oven door closed, turn the
thermostat to position 1, remove the
control knob and then adjust the screw
on top of the control knob shaft until a
steady flame of the right size is obtained.
18
Too much air
Too little air
Correct flame