Pressure Switch Adjustment; Air Pressure Switch - Check Co; Gas Minimum Pressure Switch - Riello RLS 70 Installation, Use And Maintenance Instructions

6.9

Pressure switch adjustment

6.9.1

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. 38).
With the burner operating in 1st stage, increase adjustment
pressure by slowly turning the relevant knob clockwise until the
burner locks out.
Then turn the knob anticlockwise by about 20% of the set point
and repeat burner start-up to ensure it is correct.
If the burner locks out again, turn the knob slightly anticlockwise.
as a rule, the air pressure switch must limit the CO
in the fumes to less than 1% (10,000 ppm).
To check this, insert a combustion analyser into
ATTENTION
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 1%.
The incorporated air pressure switch can work in a 'differential'
mode if connected with two pipes. If a strong depression in the
combustion chamber during the pre-purging phase does not
allow the air pressure switch to switch, this can be obtained by
applying a second tube between the air pressure switch and the
suction inlet of the fan. In this way, the pressure switch will work
in differential mode.
The use of the air pressure switch with differential
operation is allowed only in industrial applications
and where rules enable the air pressure switch to
control only fan operation without any reference to
ATTENTION
CO limit.
6.9.2

Gas minimum 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. 39).
With the burner operating at maximum output, increase the
pressure. With the burner operating in 2nd stage, increase the
adjustment pressure by slowly turning the relative knob clockwise
until the burner stops.
Then 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).
1 kPa = 10 mbar
ATTENTION
Start-up, calibration and operation of the burner
33 GB
D3854
Fig. 38
D3855
Fig. 39
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