Hydraulic Connections - Riello RL 25 BLU TC Installation, Use And Maintenance Instructions

(A)
(C)
(B)
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2
3
4
SINGLE-PIPE SYSTEMS
There are two solutions possible:
• Pump external by-pass (A) (recommended)
• Pump internal by-pass (B)
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-
D828
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 (C)
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)(A) pag. 15.
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.
Pass the hoses through the holes on the left-
hand plate 5)(C), removing the thin diaphragm
that closes the two holes or as per the following
5 instructions: unscrew the screws 1), now divide
the insert piece into its two parts 2) and 3) and re-
move the thin diaphragm blocking the two pas-
sages 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.
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11
Connect the two flexible hoses to an automatic
degassing unit, see Accessory on page 17.
In this case screw 7), must not be removed
(see diagram A on page 15):
pump internal by-pass closed.
Connect only the flexible suction hose to the
pump.
Remove screw 7), (diagram A on page 15),
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.