20032186
18
GB
Hydraulic systems
6.2
Two pipe system
Vacuum two pipe systems (Fig. 13) have a negative fuel pressure
(depression) on intake to the burner.
Usually the tank is lower than the burner.
The return line should terminate in 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 arrives over the fuel level, the
non-return valve is indispensable. This solution however is less
safe than previous one, due to the possibility of leakage of the
valve.
6.2.1
Priming pump
On the system in Fig. 13 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.
Tab. D
H
difference of level
L
maximum length of the suction line
I.D.
internal diameter of the oil pipes
NOTE:
The Tab. D shows the maximum approximate lengths for the sup-
ply line, depending on the difference in level, length, and the di-
ameter of the fuel conduit.
CAUTION
You are advised to use additional filters on the fuel
supply line.
Riello recommends a good quality fuel filter at the
tank (Fig. 13) and a secondary filter (60
for gas
oil and 15
for kerosene) are used to protect the
burner pump and nozzle from contamination.
In case of bio fuel use, pay attention to install Bio-
compatible filters.
WARNING
Before starting the burner make sure that the re-
turn pipe-line is not clogged: any obstruction
would cause the pump seals to break.
WARNING
The pump vacuum should not exceed a maximum
of 0.4 bar (30 cm Hg).
Beyond this limit gas is released from the oil.
H
metres
L metres
I.D. (8 mm)
I.D. (10 mm)
0
35
100
0.5
30
100
1
25
100
1.5
20
90
2
15
70
3
8
30
3.5
6
20
Fig. 13
H
max. 4 m
H
D10011
