I
NSTRUCTION
M
ANUAL
25
– See Fig. 5.1 –
The working pressure is determined by the tension of the
spring (8) in the regulating valve (RV). This tension is
increased to raise the working pressure and decreased to
lower it by turning the adjusting wheel (6) clockwise and anti-
clockwise repectively.
To adjust the normal working pressure, proceed as follows:
1. Start and warm up the engine; load the compressor but do
not open the outlet valves. Check the unloading pressure
which should be approx. 1 - 1.5 bar above the normal
working pressure. If the receiver pressure is less, loosen
check nut (7) and turn adjusting wheel (6) a fraction of a
turn at a time, clockwise until the right unloading pressure
is obtained.
2. Open an outlet valve just enough to maintain the normal
working pressure in the air receiver. Check that the engine
speed control lever (5) is against the maximum speed stop
screw. If not, slowly turn the adjusting wheel clockwise until
the lever buts against the screw. The piston rod (3) of the
speed regulator is in its full-out position and the engine
runs at its pre-set maximum load speed.
3. While maintaining the normal working pressure in the air
receiver, turn the adjusting wheel, a fraction of a turn at a
time, anti-clockwise until the engine just starts
decelerating. Next, turn the adjusting wheel 1/4 of a turn
clockwise. Repeat the operation, if necessary, and lock the
wheel with its check nut (7).
4. Close the outlet valve(s) to decelerate the engine to its
unloading speed. The piston rod of the speed regulator
should then be in its full-in position and piston (4) rest
against its stop in the regulator.
5. Check the unloading speed. Adjust, if necessary, the
length of the speed regulator operating rod by means of
ball-and-socket joint (2). Tighten the check nut (1) of the
ball joint after adjustment.
1.
Never operate the engine below its unloading
speed.
2.
Never exceed the maximum (unloading)
pressure.
5.2
A
IR FILTER ENGINE
/
COMPRESSOR
5.2.1 M
AIN PARTS
Fig. 5.2
Air filter
1
Filter housing
2
Cyclone blades
3
Filter element
4
Baffle
5
Retaining nut, filter element
6
Dust trap
7
Snap clips
5.2.2 R
ECOMMENDATIONS
The Atlas Copco air filters are specially designed
for the application. The use of non-genuine air
filters may lead to severe damage of engine
and /or compressor element.
Never run the compressor without air filter
element.
New elements must also be inspected for tears or punctures
before installation.
Discard the filter element (3) when damaged.
Never use oil in the dust trap.
The vacuum indicator can be reset by pushing the reset
button in the extremity of the body (Fig. 5.3, 9).
5.2.3 C
LEANING THE DUST TRAP
1
Release the two snap clips (7) that secure the dust trap to
the filter body and remove the trap.
2
Pry off the plastic baffle (4) from the trap and empty the
latter.
3
Clean the trap and baffle and reassemble them, taking
care that the slot in the baffle fits over the stud of the trap.
4
Reinstall the trap on the filter body, with the side marked
”TOP” upwards, and secure it with the clips.
1 2
3
6
7
4
5
7
Summary of Contents for XAS 175 Dd
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