Riello RG4F Installation, Use And Maintenance Instructions page 44

PRESSURISED ONE PIPE SYSTEMS
PRESSURISED ONE PIPE SYSTEMS
Pressurised systems have a positive fuel pressure
on intake 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. 9, the Tab. B 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
It is sufficient to loosen the suction gauge connection
(6, Fig. 8, on page 5) and wait until oil flows out.
DEPRESSURISED SYSTEMS
Depressurised systems have a negative fuel pressu-
re (depression) on intake to the burner. Usually the
tank is lower than the burner.
In the systems in Fig. 10, 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.
A
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;
Ø i = internal diameter of the oil pipes.
2903004
PRIMING PUMP
On the systems in Fig. 10 start the burner and wait
for the priming. Should lock-out occur prior to the ar-
rival of the fuel, await at least 20 seconds before re-
peating the operation.
In two pipe vacuum systems (B - Fig. 10) 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
H
meters
0,5
1
1.5
2
H
meters
0
0.5
1
1.5
2
3
3.5
6 GB
L meters
Ø i Ø i
8 mm 10 mm
10 20
10 40
40 80
60 100
B
L meters
Ø i Ø i
8 mm 10 mm
35 100
30 100
25 100
20 90
15 70
8 30
6 20
D5745
Fig. 9
Tab. B
D5744
Fig. 10
Tab. C