To Prepare For Check Of The Cut-Off Pressure; To Check Cut-Off Pressure; To Put The Machine Pressure In Basic Setting - Husqvarna PW 450 Workshop Manual

2.10.4 To prepare for check of the cut-off
pressure
After installation of a new control piston, the cut-off
pressure must be checked and, if necessary, set
correctly at the control piston. Setting takes place during
operation at maximum working pressure.
1. Switch off the machine and squeeze the trigger on the
spray gun until unit is depressurized.
2. Remove the shroud.
3. Connect the test pressure gauge between the high-
pressure hose (1) and the spray gun (2)
4. Connect the water inlet and the high pressure hose.
5. Turn the gear wheel (1) of the control piston
counterclockwise as far as it will go to set the machine to
maximum working pressure.
6. The removed rotary knob (2) can be used to turn the
geared wheel:
7. Position the rotary knob (2) and turn it clockwise
8. If necessary, set high-pressure nozzle to maximum
pressure

2.10.5 To check cut-off pressure

1. Start machine and open the spray gun for
approximately 15 seconds.
2. Close spray gun and read cut-off pressure on the
pressure gauge after approx. 5 seconds.
The cut-off pressure should be approx. 25 bar above the
maximum indicated working pressure.
If the value is too high or too low, the control piston must
be adjusted.
2.10.6 To put the machine pressure in basic
setting
1. Unscrew the lock nut (1) : Turn the adjusting nut (2)
approximately 1-2 turns counterclockwise.
2. Switch on the machine and squeeze the trigger on
the spray gun.
3. Turn the adjusting nut (2) clockwise until the reading
on the pressure gauge no longer increases (maximum
working pressure).
4. Slowly adjust the nut (2) counter clockwise until the
pressure falls by approx. 5 bar.
5. Turn the adjusting nut (2) 1/2 turn clockwise.
6. Recheck cut-off pressure.
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