12
AIR PRESSURE SWITCH (A)
CO CHECK
Adjust the air pressure switch after having per-
formed all other burner adjustments with the air
pressure switch set to the start of the scale (A).
With the burner working at MIN output, insert a
combustion analyser in the stack and slowly
close the fan suction line inlet (for example, with
cardboard) until the Bacharach index is equal
to 2.
Slowly turn the appropriate knob clockwise until
the burner goes into lockout.
Check the indication of the arrow pointing
upwards on the graduated scale (A). Turn the
knob clockwise again, until the value show on
the graduated scale corresponds with the arrow
pointing downwards (A), and so recovering the
hysteresis of the pressure switch represented
by the white mark on a blue background,
between the two arrows.
Now check the correct start-up of the burner.
If the burner locks out again, turn the knob
slightly in an anticlockwise direction.
(A)
AIR PRESSURE SWITCH
D3951
