Sime Murelle 20 BFT, Manual

Page: 95 / 108

95
ES
PT
GB
3.9 FUMES PRESSURE SWITCH
vers. BF-BFT
The pressure switch is calibrated by the
manufacturer at the following values:
5.3 - 6.3 H
2
O for vers. “25 BF - 25 BFT”
3.6 - 4.6 H
2
O for vers. “30 BF”
4.6 - 5.6 H
2
O for vers. “20 BF - 35 BFT”
which can guarantee boiler functioning also
with aspiration and discharge pipes of the
maximum length allowed.
The value of the signal to the pressure swit-
ch is measured by a differential pressure
gauge connected as indicated in fig. 16.
3.10 WATER
FLOW GUAGE
The water flow gauge (8 fig. 4) intervenes,
blocking burner functioning, if it detects
that there is insufficient water circulating in
the primary circuit (< 450 l/h).
To r es t or e bur ner functioning, check
system pressure and the functioning of the
pump and the flow switch, and the cleaning
of the “Aqua Guard Filter System” filter.
3.11 HEAD AVAILABLE
TO SYSTEM
Residual head for the heating system is
shown as a function of rate of flow in the
graph in fig. 17.
To obtain the maximum head available to
the system, turn off the by-pass by turning
the union to the vertical position (fig. 17/a).
Fig. 16
0
200 1600 1400 1200 1000 800 600 400
PORTATA (l/h)
PREV
ALENZA RESIDU
A (mbar)
500
400
100
200
300
30-35
25
Mur
elle
600
30-35
25
By-pass inserito
By-pass escluso
Fig. 17
By-pass inserito
By-pass escluso
Fig. 17/a
RESIDU
AL
HEAD (mbar)
FLOW RATE (l/h)
By-pass off
By-pass on
By-pass on
By-pass off