8
HYDRAULIC SYSTEM
FUEL SUPPLY
Double-pipe circuit (A)
The burner is equipped with a self-priming pump which
is capable of feeding itself within the limits listed in the
table at the left.
The tank higer than the burner A
The distance "P" must not exceed 32 ft in order to
avoid subjecting the pump's seal to excessive strain;
the distance "V" must not exceed 13 ft in order to per-
mit pump self-priming even when the tank is almost
completely empty.
The tank lower than the burner B
Pump suction values higher than 6.5 PSI must not be
exceeded because 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 re-
turning to the tank with an auxiliary pump that circu-
lates the fuel under pressure. A branch connection
from the loop goes to feed the burner. This circuit is ex-
tremely useful whenever the burner pump does not
succeed in self-priming because the tank distance
and/or height difference are higher than the values list-
ed in the table.
Key (A)
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
HYDRAULIC CONNECTIONS (B)
The pumps are equipped with a by-pass that connects
return line and suction line. The pumps are installed on
the burner with the by-pass closed by screw 6)(A)p.12.
It is therefore necessary to connect both hoses to the
pump.
The pump seal will be damaged immediately if it is
run with the return line closed and the bi-pass
screw inserted.
Remove the plugs from the suction and return connec-
tions of the pump.
Insert the hose connectors with the supplied seals into
the connections and screw them down.
Take care that the hoses are not stretched or twisted
during installation.
Install the hoses where they cannot be stepped on or
come into contact with hot surfaces of the boiler.
Now connect the other end of the hoses to the supplied
nipples, using two wrenches, one to hold the nipple
steady while using the other one to turn the rotary un-
ion on the hose.
(A)
+ H
- H
(ft)
L (ft)
RL 70
RL 100 - 130
Ø (inch)
Ø (inch)
3/8”
1/2”
5/8”
3/8”
1/2”
5/8”
+ 13
168
368
493
234
454
493
+ 10
148
326
493
204
401
493
+ 6.6
128
283
493
174
399
493
+ 3.3
105
240
474
145
296
493
+ 1.6
95
217
434
132
270
493
0
85
197
395
118
243
451
- 1.6
76
178
355
105
217
405
- 3.3
66
155
316
92
191
359
- 6.6
43
112
234
63
138
266
- 10
23
69
151
33
86
174
- 13
–
26
69
–
33
82
(B)
A
B
1
2
3
7
5
6
6
4
7
5
3
15
/ 16
”
- H
+ H
V
P
D737
HYDRAULIC CONNECTIONS
D2328
