21
20033090
GB
Installation
5.11.2 Single-pipe circuit
There are two solutions possible:
• Pump external bypass (A, Fig. 19) (recommended)
The two hoses are connected to an automatic degassing unit,
(See “Degassing unit” on page 35.).
The pump bypass screw must not be removed.
• Pump internal bypass (B, Fig. 19)
The pumps are equipped with a screw 6), Layout on Fig. 31,
which is accessible through the return line connector, which
when removed opens the return pipe to the suction line. The
pump return line connector must be plugged.
This solution is possible only with low pump depression values
(max. 0.2 bar) and perfectly-sealed piping.
Key (Fig. 18)
H
Pump/Foot valve height difference
L
Piping length
• values calculated for gas oil:
• viscosity = 6 cSt/20°C
• density = 0.84 kg/dm
3
• temperature = 0°C
• max altitude = 200 m (a.s.l.)
ø
Inside pipe diameter
1 Burner
2 Pump
3 Filter
4 Manual
on/off
valve
5 Suction
line
6 Foot
valve
7
Rapid closing manual valve remote controlled (only Italy)
8
On/off solenoid valve (only Italy)
11 Tank filter
Tab. I
10
cm
11
5
2
4
6
7
5
P
V
8 +H
1
A
3
Fig. 18
S8274
+ H
- H
(m)
L (m)
Ø (mm)
8
10
12
+ 4,0
35
90
152
+ 3,0
30
80
152
+ 2,0
26
69
152
+ 1,0
21
59
130
+ 0,5
19
53
119
Fig. 19
D349
A
B
