Intermediate Outputs; Air Pressure Switch - Riello RS 55/M BLU Installation, Use And Maintenance Instructions

6.6.4

Intermediate outputs

Gas adjustment
No adjustment of gas delivery is required.
Air adjustment
Slightly press the button 2)(Fig. 26 on page 23) "output increase"
(  +) so that a new screw 5)(Fig. 28) appears inside the opening
6)(Fig. 28); adjust it until optimal combustion is achieved. Pro-
ceed in the same way with the other screws.
Take care that the cam profile variation is progressive.
Switch the burner off with the switch 1)(Fig. 26 on page 23), po-
sition OFF. Release the variable profile cam by putting the servo-
motor slot 2) (Fig. 28) in a vertical position and check more than
once, rotating the cam forward and backward by hand, that the
movement is soft and smooth, without sticking.
As far as possible, try not to move those screws at the ends of the
cam that were previously adjusted for the opening of the air
damper to MAX and MIN output.
NOTE:
Once you have finished adjusting outputs MAX - MIN - INTER-
MEDIATE, check ignition once again: noise emission at this
stage must be identical to the following stage of operation. If you
notice any sign of pulsations, reduce the ignition stage delivery.
6.6.5

Air pressure switch

The air pressure switch can be connected in differential mode
1)(Fig. 30), i.e. it is under pressure either by the depression or
pressure generated by the fan. In this way the burner can operate
even in combustion chambers in depression and with high mod-
ulation ratios: MIN / MAX outputs of up to 1/6.
In this case the air pressure switch needs no adjustment and its
function is limited to controlling fan operation.
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
WARNING
CO limit.
In civil applications the pipe from the fan air inlet
should be removed, see 2)(Fig. 30), and the pres-
sure switch must be adjusted as follows.
Air pressure switch connected as in 2)(Fig. 30)
Adjust the air pressure switch after performing all other burner
adjustments with the air pressure switch set to the start of the
scale (Fig. 29).
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 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 anticlockwise a little bit more.
Start-up, calibration and operation of the burner
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 the
chimney, slowly close the fan suction inlet (for ex-
WARNING
ample with cardboard) and check that the burner
locks out, before the CO in the fumes exceeds 1%.
D3854
1)
2)
25 GB
D794
Fig. 29
Fig. 30
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