6
I
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 side.
The tank higher than the burner
A
Distance "P" must not exceed 10 meters in
order to avoid subjecting the pump's seal to
excessive strain; distance "V" must not exceed
4 meters in order to permit pump self-priming
even when the tank is almost completely empty.
The tank lower than the burner
B
Pump depression values higher than 0.45 bar
(35 cm Hg) 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 depart-
ing from and returning to the tank with an auxil-
iary 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 suc-
ceed in self-priming because the tank distance
and/or height difference are higher than the val-
ues listed in the Table.
Key
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 = Rapid closing manual valve remote con-
trolled (only Italy)
8 = On/off solenoid valve (only Italy)
9 = Return line
10 = Check valve (only Italy)
•
HYDRAULIC CONNECTIONS (B)
The pumps are equipped with a by-pass that
connects return line with suction line. The
pumps are installed on the burner with the by-
pass closed by screw 6)(B)p.11.
It is therefore necessary to connect both hoses
to the pump.
The pump will break down immediately if it is run
with the return line closed and the by-pass
screw inserted.
Remove the plugs from the suction and return
connections of the pump.
Insert the hose connections 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
suction and return lines by using the supplied
nipples.
(A)
(B)
+ H
- H
(m)
L (m)
Ø (mm)
12
14
16
+ 4,0
71
138
150
+ 3,0
62
122
150
+ 2,0
53
106
150
+ 1,0
44
90
150
+ 0,5
40
82
150
0
36
74
137
- 0,5
32
66
123
- 1,0
28
58
109
- 2,0
19
42
81
- 3,0
10
26
53
- 4,0
-
10
25
D701
D3331
Summary of Contents for TECNO 190-L
Page 47: ......
