Air Pressure Switch - Riello RS 55/E BLU Installation, Use And Maintenance Instructions

6.5.3

Air pressure switch

Adjust the air pressure switch after performing all other burner
adjustments with the air pressure switch set to the start of the
scale (Fig. 33).
With the burner working at MIN output, insert a combustion ana-
lyser in the stack, slowly close the suction inlet of the fan (for
example, with a piece of cardboard) until the CO value does not
exceed 100 ppm.
– Slowly turn the appropriate knob clockwise until the burner
goes into lockout.
– Check the indication of the arrow pointing upwards on the
graduated scale.
– Turn the knob clockwise again, until the value shown on the
graduated scale corresponds with the arrow pointing down-
wards, and so recovering the hysteresis of the pressure
switch (shown by the white mark on a blue background, be-
tween the two arrows).
– Now check the correct start-up of the burner.
– If the burner locks out again, turn the knob anticlockwise a lit-
tle bit more.
During these operations it may be useful to measure the air
pressure with a pressure gauge.
The connection of the pressure gauge is shown in Fig. 33. The
standard configuration is that with the air pressure switch con-
nected in absolute mode. Note the presence of a "T" connection,
not supplied.
In certain applications in strong depression situations, the con-
nection of the pressure switch does not allow it to change over.
In this case it is necessary to connect the pressure switch in dif-
ferential mode, applying a second tube between the air pressure
switch and the fan suction line mouth. In this case also, the pres-
sure gauge must be connected in differential mode, as shown in
Fig. 33.
20040563
Start-up, calibration and operation of the burner
D3951
+
_
Connecting the
pressure gauge
with the pressure
switch in abso-
lute mode
30 GB
+
D8153
Connecting the
pressure gauge
with the pressure
switch in differ-
ential mode
_
Fig. 33