20039735
6
GB
Pressurised systems have a positive fuel pressure on in-
take to the burner. Usually the tank is higher than the
burner, or the fuel pumping systems are on the outside of
the heat generator.
In the system in fig. 6, the table shows the maximum indi-
cated lengths for the supply line, depending on the differ-
ence in level, length and the diameter of the oil pipes.
PRIMING PUMP
It is sufficient to loosen the suction gauge connection
(5, fig. 5) and wait until oil flows out.
Depressurised systems have a negative fuel pressure (de-
pression) on intake to the burner. Usually the tank is lower
than the burner.
In the systems in figs. 7 and 8, the table shows the maxi-
mum indicated lengths for the supply line, depending on the difference in level, length and the diameter of
the oil pipes.
PRIMING PUMP
On the systems in figs. 7 and 8 start the burner and wait for the priming. Should lock-out occur prior to the
arrival of the fuel, await at least 20 seconds before repeating the operation.
In two pipe vacuum systems (fig. 8) the return line should terminate within the oil tank at the same level as
the suction line. In this case a non-return valve is not required.
Should however the return line arrive over the fuel level, a non-return valve is required. This solution is
less reliable than the previous one, as the valve seal could be damaged.
PRESSURISED ONE PIPE SYSTEMS
(fig. 6)
H
meter
s
L meters
I. D.
8 mm
I. D.
10 mm
0.5
1
1.5
2
10
20
40
60
20
40
80
100
SYSTEM NOT PERMITTED
IN GERMANY
Fig. 6
H
max. 4 m
D5703
DEPRESSURISED SYSTEMS
(fig. 7 and 8)
H
meters
L meters
I. D.
8 mm
I. D.
10 mm
0
0.5
1
1.5
2
3
3.5
35
30
25
20
15
8
6
100
100
100
90
70
30
20
NOTES VALID FOR ALL SYSTEMS
The installer must ensure that the supply depression is not above 0.4 bar
(30 cm Hg). Above that level, gas leaks out from the fuel.
The pipes must all be perfectly sealed.
H
= difference of level;
L
= max. length of the suction line;
I. D.
= internal diameter of the oil pipes.
Fig. 7
Fig. 8
H
max. 4 m
ma
x. 4 m
H
H
H
D5705
