Riello P 300 P/G Installation, Use And Maintenance Instructions page 23

6.11.1 Hydraulic connections
 Make sure that the hoses to the pump supply
and return line are installed correctly.
CAUTION
The pumps are equipped with a by-pass that connects return line
with suction line. They are installed on the burner with the by-
pass closed by screw 6)(Fig. 19).
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 plugs from suction and return connectors of the pump.
Insert the hose connections with the supplied seals into the
connections and screw them down.
Install the hoses where they cannot be stepped on or come into
contact with hot surfaces of the boiler.
Finally, connect, the other end of the hoses to the suction line and
return line ducts using the nipples supplied with the equipment.
During the installation, hoses must not be
stressed with twisting.
ATTENTION
Installation
6.11.2 Hydraulic circuit diagram
VS VF
FO
VR1
VR PO
C2
P
Cn - Control cams
FO - Oil filter
MM - Delivery pressure gauge
MR - Return pressure gauge
P - Pump with filter and pressure adjuster
RO - Pressure adjuster on return line
21 GB
MM
SM
RO
C1
MR
MV
D2583
Fig. 18
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