10
SINGLE-PIPE SYSTEMS
There are two solutions possible:
• Pump external by-pass (A) (recommended)
Connect the two flexible hoses to an automatic
degassing unit, see Accessory on page 31.
In this case screw 7), must not be removed
(see diagram on page 27):
pump internal by-pass closed.
• Pump internal by-pass (B)
Connect only the flexible suction hose to the
pump.
Remove screw 7), (diagram page 13), which
can be accessed from the return union:
pump internal by-pass open.
Plug the pump return line connection.
This solution is possible only with low pump
depression values (max. 0.2 bar) and perfect-
ly-sealed piping.
THE LOOP CIRCUIT
A loop circuit consists of a loop of piping depart-
ing from and returning to the tank with an auxilia-
ry pump that circulates the fuel under pressure.
A branch connection from the loop goes to feed
the burner. This circuit is extremely useful when-
ever 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.
HYDRAULIC CONNECTIONS
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 7)(B) pag. 13.
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.
Route the hoses through the holes in the plate,
preferably using those on the rh side, fig. (C): un-
screw the screws 1), now divide the insert piece
into its two parts 2) and 3) and remove the thin
diaphragm blocking the two passages 4). 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 union on the hose.
HYDRAULIC CONNECTIONS
D10323
(C)
(B)
(A)
D828
