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5.12
Hydraulic operation diagram
5.12.1 Oil pressure switch
Burner halt condition
Can be adjusted between 2 and 15 bar; in the event of
excessive counter-pressure on the fuel return line, it brings the
burner to a halt, (recommended calibration: 5 bar).
5.13
Pressure variator
To calibrate cam 8)(Fig. 19):
remove gear-case 9), slacken screws 7), and act on screw
4) until required eccentricity is obtained.
Turning screw 4) to the right (+ sign), eccentricity is
increased, thus increasing the difference between nozzle
maximum and minimum delivery.
Turning screw 4) to the left (- sign), eccentricity is reduced,
thereby reducing the difference between nozzle maximum
and minimum delivery.
Every variation of eccentricity may require a travel offset
using nut and locknut 6).
Note
•
To obtain correct calibration, cam 8) must operate over the
full travel range of the servomotor (20° - 130°): every
variation of the servomotor must be matched by a variation in
pressure.
•
Never give the variator piston a snug fit: stop ring 5) sets
maximum travel.
•
When the adjustment has been made, manually check that
there is no Knocking between 20° and 130° and that
maximum and minimum pressures match pre-selected
values as indicated on the graph (Fig. 14 on page 19).
•
If, at maximum nozzle delivery (maximum return pressure),
pressure oscillations are seen on pressure gauge 3), slightly
reduce pressure until the oscillations are eliminated.
20176605
Installation
Key (Fig. 18)
Cn
- Control cams
FO
- Oil filter
MM
- Delivery pressure gauge
MR
- Return pressure gauge
MV
- Fan motor
P
- Pump with pressure adjuster
POM
- Maximum oil pressure switch
RO
- Pressure adjuster on return line
Vn
- Valves
Key
1
Pressure switch fitting
2
Delivery pressure gauge
3
Return pressure gauge
4
Cam adjustment screw
5
Piston halt ring
6
Piston calibration nut and locknut
7
Cam locking screws
8
Variable cam
9
Cover
22
GB
S7980
Fig. 18
S7969
Fig. 19
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