Pump; Pressure Adjustment; Pressurised One-Pipe Systems; Priming Pump - Riello RG2 Installation, Use And Maintenance Instructions

5.13.2 Pump

The pump is designed to allow working with two pipes.
Before starting up the burner, make sure that the return pipeline
is not clogged.
An excessive back pressure ( 1 bar) would cause the damage
of the pump seal, with subsequent fuel leaks inside the burner.
The suction line plug 1)(Fig. 19) is made of plastic.
Once removed, it must not be used again.
In single-pipe installations, the plug in the return
WARNING
line 2) must be totally in steel.
The pump has a delivery pressure regulation device 4)(Fig. 19).
Pressure increases if turned in a clockwise direction, and de-
creases if turned in the other direction. An indication of sensitivity
is 1 bar per turn.
The pressure can be regulated in a range of 8 - 15 bar.

5.13.3 Pressure adjustment

 The pump leaves the factory set at 12 bar.
 If necessary, recalibrate the pressure using the screw 5) Fig.
19.
8
1
2 3 4
1 Suction line
2 Return line
3 By-pass screw
4 Gauge connection
5 Pressure adjuster
6 Vacuum gauge connection
7 Valve
8 Auxiliary pressure test point
20136866
Installation
D5487
5 6
7
Fig. 19
22

5.13.4 Pressurised one-pipe systems

Pressurised one-pipe systems (Fig. 20) have a positive fuel pres-
sure on intake to the burner.
Usually the tank is higher than the burner, or the fuel pumping
systems are on the outside of the boiler.
In order to obtain one pipe working it is necessary to unscrew the
return line plug 2)(Fig. 19), remove the by-pass screw 3)(Fig. 19)
and then screw the plug 2)(Fig. 19) in again with a tightening
torque of 0.5 Nm.
S9666
H
metres
0.5
1
1.5
2
H = Difference of level
L = Maximum suction line length
Ø = Inner diameter of the pipe
The installer must ensure that the power supply
pressure never exceeds 0.4 bar (30 cm Hg).
Above that level, the pump seal is subject to too
WARNING
much stress.
In the system in Fig. 20, the table shows the maximum approxi-
mate lengths for the supply line, depending on the difference in
level, the length and the diameter of the fuel conduit.

5.13.5 Priming pump

In the system of Fig. 20 just loosen the connection of the vacuom-
eter 6)(Fig. 19) and wait for the fuel to come out.
In the systems A and B of Fig. 21 start the burner and wait for the
priming.
Should lockout occur prior to the arrival of the fuel, await at least
20 seconds before repeating the operation.
The pump vacuum should not exceed a maximum of 0.4 bar (30
cm Hg).
Beyond this limit gas is released from the oil.
The pipes must all be perfectly sealed.
WARNING
GB
L metres
Ø (8 mm) Ø (10 mm)
10 20
20 40
40 80
60 100
Fig. 20
Tab. F