Air Pressure Switch; High Gas Pressure Switch; Low Gas Pressure Switch - Riello RLS 70 Installation Instruction

4.18 Air pressure switch

Adjust the air pressure switch after having performed all other burn-
er adjustments with the air pressure switch set to the start of the
scale (Fig. 36).
With the burner operating at min. output, increase adjustment pres-
sure by slowly turning the relative dial clockwise 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.
as a rule, the air pressure switch must prevent the
formation of CO.
To check this, insert a combustion analyser into the
WARNING
chimney, slowly close the fan suction inlet (for ex-
ample with cardboard) and check that the burner
locks out, before the CO in the fumes exceeds 400
ppm.

4.19 High gas pressure switch

Adjust the high gas pressure switch after having performed all oth-
er burner adjustments with the maximum gas pressure switch set
to the end of the scale (Fig. 37).
With the burner operating at MAX output, reduce the adjustment
pressure by slowly turning the adjustment dial anticlockwise until
the burner locks out.
Then turn the dial clockwise by 0.8" WC and repeat burner firing.
If the burner locks out again, turn the dial again clockwise by 0.4"
WC.

4.20 Low gas pressure switch

Adjust the low gas pressure switch after having performed all the
other burner adjustments with the pressure switch set at the start
of the scale (Fig. 38).
With the burner operating at MAX output, increase adjustment
pressure by slowly turning the relative dial clockwise until the burn-
er 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.
Installation
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
pressure switch and the suction inlet of the fan. In such a manner
the air pressure switch operates as differential pressure switch.
23
AIR PRESSURE SWITCH
D2548
HIGH GAS PRESSURE SWITCH
D2547
LOW GAS PRESSURE SWITCH
D2547
Fig. 36
Fig. 37
Fig. 38
6046