Installation
23
20036952
GB
4.11
Hydraulic system
4.11.1
Fuel supply
Double-pipe circuit
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.
The tank higher than the burner A
Distance "P" must not exceed 33 ft in order to avoid subjecting the
pump's seal to excessive strain; distance "V" must not exceed 13 ft
in order to permit pump self-priming even when the tank is almost
completely empty.
The tank lower than the burner B
Pump suction values higher than 13 ft must not be exceeded be-
cause at higher levels gas is released from the fuel, the pump starts
making noise and its working life-span 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 less probable
that the suction line fails to prime or stops priming.
The loop circuit
A loop circuit consists of a loop of piping exiting and returning to the
tank with an auxiliary pump that circulates the fuel under pressure.
A branch connection from the loop goes to feed the burner.
This circuit is extremely useful whenever the burner pump does not
succeed in self-priming because the tank distance and/or height
difference are higher than the values listed in the table below.
H
Pump/foot valve height difference
L
Piping length
Ø Inside pipe diameter
1
Burner
2
Pump
3
Filter
4
Manual on/off valve
5
Suction line
6
Foot valve
7
Return line
V
Max distance 13 ft
+ H
- H
(ft)
L (ft)
Ø (inch)
3/8”
1/2”
5/8”
+ 13
234
454
493
+ 10
204
401
493
+ 6.6
174
399
493
+ 3.3
145
296
493
+ 1.6
132
270
493
0
118
243
451
- 1.6
105
217
405
- 3.3
92
191
359
- 6.6
63
138
266
- 10
33
86
174
- 13
–
33
82
Fig. 19
1
2
3
7
5
6
6
4
7
5
- H
+ H
V
P
D737
3
15
/ 16
”
B
A
