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
HEAD AVAILABLE
TO SYSTEM (fig. 17 - fig. 17/a)
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).
NOTE: The expansion vessel supplied with
the boiler is suitable for heating systems
with a maximum water capacity of 80
litres. In excess of such capacity, arrange
for an additional expansion vessel.
3.11
WATER PRESSURE
VALVE (fig. 17/a)
The water pressure valve (C fig. 17/a)
intervenes, blocking burner functioning, if it
detects that there is insufficient pressure
in the boiler (< 0,6 bar).
To restore burner functioning, to bring back
the pressure of the boiler at values compri-
se between 1 - 1,2 bar.
0
200
1600
1400
1200
1000
800
600
400
PORTATA (l/h)
PREV
ALENZA RESIDU
A (mbar)
500
400
100
200
300
Fo
rm
at
D
G
T
600
By-pass inserito
By-pass escluso
83
ES
PT
ENG
RESIDU
AL
HEAD
(mbar)
FLOW RATE (l/h)
PRESSOSTATO
VENTILATORE
CAMERA STAGNA
(+)
(--)
Fig. 16
Fig. 17
A
B
C
RIFERIMENTO POSIZIONE BY-PASS
Fig. 17/a
LEGENDA
A
By-pass on
B
By-pass off
C
Water pressure valve
By-pass on
By-pass off
SEALED CHAMBER
FAN
PRESSURE SWITCH
REFERENCE POSITION BY-PASS
