17
20098582
GB
Installation
5.11
Fuel supply
The burner is equipped with a self-priming pump which is capable
of feeding itself within the limits listed in the table at the side.
There are three types of fuel hydraulic circuits:
–
Double-pipe circuits (the most common)
–
Single-pipe circuits
–
Loop circuits
According to the burner/tank layout, either of two fuel supply sys-
tems can be used:
–
Siphon-type (with the tank higher than the burner)
–
Suction-type (with the tank lower than the burner)
5.11.1
Double-pipe siphon-type systems A)(Fig. 18)
The distance “P” must not exceed 10 meters in order to avoid
subjecting the pump's seal to excessive strain; the distance “V”
must not exceed 4 meters in order to permit pump self-priming
even when the tank is almost completely empty.
5.11.2
Double-pipe suction-type systems B)(Fig. 18)
Pump depression values higher than 0.45 bar (35 cm Hg) must
not be exceeded because at higher levels gas is released from
the fuel, the pump starts making noise and its working lifespan
decreases.
It is good practice to ensure that the return and suction lines enter
the burner from the same height; in this way it will be more im-
probable that the suction line fails to prime or stops priming.
Tab. J
Key (Fig. 18)
H
Pump/Foot valve height difference
L
Piping length values calculated for light 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
Return line
Useful suggestions for both systems (A) and (B)
–
Use copper pipes whenever possible.
–
Any curves used in the system should be made with the wid-
est possible radius.
–
Use biconic connectors at both ends of the pipe.
–
Whenever the burner is installed in areas with extremely cold
winter climates (temperatures lower than -10°C), we recom-
mend insulating both the tank and the piping. Avoid the small-
est of the three pipe diameters provided in the Table and lay
the piping along the most sheltered route possible. The par-
affin in the fuel begins to solidify below 0°C, and the filters
and nozzle begin to clog accordingly.
–
Install a filter on the suction lines with a transparent plastic
bowl if possible in order to permit the regular flow of fuel and
quick checking of the state of the filter.
–
The return pipe does not require an on/off valve, but if the
user desires to insert one, a lever-type valve should be se-
lected which clearly indicates when the valve is open or
closed (if the burner starts with the return pipe closed, the
sealing organ located on the pump shaft will break).
Explosion danger due to fuel leaks in the pres-
ence of a flammable source.
Precautions: avoid knocking, attrition, sparks and
heat.
Make sure the fuel interception tap is closed be-
fore performing any operation on the burner.
WARNING
The fuel supply line must be installed by qualified
personnel, in compliance with current standards
and laws.
+/- H
m
L (m)
Ø 8 mm
Ø 10 mm
Ø 12 mm
+4
+3
+2
+1
+0,5
35
30
26
21
19
90
80
69
59
53
152
152
152
130
119
0
17
48
108
-0,5
-1
-2
-3
-4
15
13
9
4
-
43
37
27
16
6
97
86
64
42
20
Fig. 18
D396
A
B