Instruction Manual Breathing Air Compressors
39
4.5.5. PRESSURE MAINTAINING VALVE
DESCRIPTION
A pressure maintaining valve is integrated in the P31 filter
base (Abb. 48), or mounted at the outlet of the filter system
P41 (Abb. 49).
It ensures that pressure is built up in the filter even from the
start of delivery, thus achieving a constant, optimum filtra
tion. It will also guarantee proper working conditions for the
final stage cylinder.
The pressure maintaining valve is adjusted to 150 ±10 bar.
MAINTENANCE
The pressure maintaining valve (Abb. 48) is adjusted at the
factory to the required pressure and normally does not re
quire regular maintenance or readjustment. In case of read
justment becoming necessary, loosen jam nut (2) and set
screw (3). Adjust screw (1) to the required pressure using a
suitable screw-driver.
Clockwise = increase pressure
Counter-clockwise = decrease pressure
4.5.6. SAFETY VALVES
DESCRIPTION
All 4 compressor stages are protected by safety valves as fol
lows
1st stage 5 bar
2nd stage 24 bar
3rd stage 95 bar
The safety valves are adjusted to the corresponding pressure
and sealed at the factory. The safety valve for protection of
the last stage is mounted on top of the filter system P31 or
P41 oil and water separator, respectively, and is adjusted to
the operating pressure of the unit (see chapter 1, Technical
Data), 225 bar (3,200 psi) or 330 bar (4,700 psi).
MAINTENANCE
Checking function
The final pressure safety valve has to be checked regularly.
For this purpose the safety valve can be vented manually.
Turn knurled knob on top of the valve clockwise until valve
blows off (Abb. 50).
Abb. 48 Pressure maintaining valve, P31
1
2
3
Abb. 49 Pressure maintaining valve, P41
Abb. 50 Venting the final pressure safety valve
VENTING
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