B&C Technologies IM Series Industrial Ironer - Manual (Page 139)

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5 - AIR PRESSURE SWITCH (A) - CO CHECK
Adjust the air pressure switch after having performed all
other burner adjustments with the air pressure switch set
to the start of the scale (A).
With the burner operating at min. output, increase adjust-
ment pressure by slowly turning the relative dial clock-
wise until the burner locks out.
Then turn the dial 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 dial anti-clockwise
a little bit more.
Attention:
As a rule, the air pressure switch must prevent the forma-
tion of CO.
To check this, insert a combustion analyser into the
chimney, slowly close the fan suction inlet (for example
with cardboard) and check that the burner locks out,
before the CO in the fumes exceeds 400 ppm.
The air pressure switch may operate in "differential"
operation in two pipe system. If a negative pressure in
the combustion chamber during pre-purging prevents
the air pressure switch from switching, switching may be
obtained by fitting a second pipe between the air pres-
sure switch and the suction inlet of the fan. In this way
the air pressure switch operates as differential pressure
switch.
6 - LOW GAS PRESSURE SWITCH (B)
Adjust the low gas pressure switch after having per-
formed all the other burner adjustments with the pressure
switch set at the start of the scale (B).
With the burner operating at MAX output, increase ad-
justment pressure by slowly turning the relative dial
clockwise until the burner locks out.
Then turn the dial anti-clockwise by 0.8” WC and repeat
burner starting to ensure it is uniform.
If the burner locks out again, turn the dial anti-clockwise
again by 0.4” WC.
FLAME PRESENT CHECK (C)
The burner is fitted with an ionisation system (flame rod)
which ensures that a flame is present. The minimum
current for operation is 6 µA. (or see appropriate docu-
mentation of flame safeguard manufacturer)
The burner provides a much higher current, so that con-
trols are not normally required. However, if it is neces-
sary to measure the ionisation current, disconnect the
plug-socket 21)(A)p.4 on the ionisation probe cable and
insert a direct current microamperometer with a base
scale of 100 µA.
Carefully check polarities!
(A)
AIR PRESSURE SWITCH
LOW GAS PRESSURE SWITCH
(B)
(C)
D795
D2548
D2547
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