Table of Contents
Advertisement
6.11
Pressure switch adjustment
6.11.1 Air pressure switch - check CO
Adjust the air pressure switch after performing all other burner
adjustments with the air pressure switch set to the start of the
scale (Fig. 36).
With the burner operating at min. output, increase adjustment
pressure by slowly turning the relative knob clockwise until the
burner locks out.
Then turn the knob anti-clockwise by about 20% of the set point
and repeat burner starting to ensure it is correct.
If the burner locks out again, turn the knob anticlockwise a little
bit more.
In conformity with the standard, the air pressure
switch must prevent the air pressure falling below
80% of the adjusted value and the CO in the flue
gases exceeding 1% (10,000 ppm).
WARNING
To check this, insert a combustion analyser into the
chimney, slowly close the fan suction inlet (for exam-
ple with cardboard) and check that the burner locks
out before the CO in the fumes exceeds 1%.
The air pressure switch is installed in the "absolute" position, that
is connected only to the pressure test point "+" 22)(Fig. 5).
6.11.2 Maximum gas pressure switch
Adjust the maximum gas pressure switch after having performed
all the other burner adjustments with the maximum gas pressure
switch set at the end of the scale (Fig. 37).
With the burner operating at maximum output, lower the adjust-
ment pressure by slowly turning the relative knob anticlockwise
until the burner locks out.
Now turn the knob clockwise by 0.2 kPa (2 mbar) and repeat the
start-up of the burner.
If the burner locks out again, turn the knob clockwise again by 0.1
kPa (1 mbar).
Start-up, calibration and operation of the burner
D3854
D3856
6.11.3 Minimum gas pressure switch
Adjust the minimum gas pressure switch after performing all the
other burner adjustments with the pressure switch set to the start
of the scale (Fig. 38).
Fig. 36
With the burner operating at maximum output, increase the ad-
justment pressure by slowly turning the relative knob clockwise
until the burner stops.
Now turn the knob anticlockwise by 0.2 kPa (2 mbar) and repeat
burner start-up to ensure it is uniform.
If the burner locks out again, turn the knob anticlockwise again by
0.1 kPa (1 mbar).
6.11.4 Minimum oil pressure switch
The minimum oil pressure switch (Fig. 39) is calibrated in the fac-
tory at 18 bar. If the oil pressure falls below this value in the de-
livery line, the pressure switch stops the burner.
The burner restarts automatically if the pressure goes above bar
value set after the burner starts.
6.11.5 Maximum oil pressure switch
The maximum oil pressure switch (Fig. 39) is calibrated in the
factory at 3 bar. If the oil pressure in the return line goes above
this value, the pressure switch stops the burner in a lockout.
To adjust the pressure switches, use a tool to operate the adjust-
ment screw, see (Fig. 39).
20079898
Fig. 37
1 kPa = 10 mbar
WARNING
37
GB
Fig. 38
D3855
Fig. 39
20084880
Advertisement
Table of Contents
