Adjusting Procedure; Adjusting The Suction Bypass; Regulating The Oil Pressure - Hitachi NEXT Series Instruction Manual

3.7 Adjusting Procedure

3.7.1 Adjusting the Suction Bypass

Valve (For Fixed-Speed type)
①④
Suction
throttle
valve
Locknut
Seal washer

3.7.2 Regulating the Oil Pressure

Oil Relief Valve
3. OPERATING PROCEDURE [Adjusting Procedure]
②④
Air intake filter
③
Adjusting Bolt
(Suction Bypass Valve)
Usually keep the bolt
tightened, but not
excessively.
① When dust particles accumulate on the valve plate of
the suction throttle valve, the suction vacuum
pressure may drop and eventually causing the
discharge air temperature to rise.
② The first steps to resolve the lower suction vacuum
pressure are as following. If the unloaded interstage
pressure drops as low as -12 psi (-0.08 MPa) or
discharge air temperature is gradually increased.
A) Clean or replace the air intake filter.
B) Clean the suction throttle valve's valve plate.
③ If the air compressor cannot be shutdown to clean
these par ts, turn the adjusting bolt (the suction
bypass valve) counterclockwise to open. This will
allow the air intake and increase the discharge air
pressure to be greater than -12 psi (-0.08 MPa) when
running unloaded.
④ Replace the consumable parts in the air intake filter
and suction throttle valve with new consumable
par ts in accor dance with the appr opriate
maintenance schedule. (
IMPORTANT
The interstage pressure of as low as -12 psi (-0.08 MPa)
during unloading period may increase the discharge air
temperature.
① Use the oil relief valve to regulate the oil pressure.
To regulate the oil pressure, open the oil relief valve
cap, loosen the lock nut, and turn the regulating bolt
to keep the oil pressure at the specified 18 psi to 23
psi (0.12 to 0.16 MPa).
・ 1 8 psi to 23 psi (0.12 to 0.16 MPa) when the ambient
temperature is 68 degree F (20 degree C) or higher.
・ 20 psi to 26 psi (0.14 to 0.18 MPa) when the
ambient temperature is 68 degree F (20 degree C)
or lower.(for V type, adjust at the maximum
operating frequency.)
② Turn the regulating bolt clockwise to increase the
oil pressure and vice versa.
③ Tighten the locknut and replace the cap.
IMPORTANT
If the oil pressure is reduced to the specified or lower, the
oil pressure sensor detects it and shutdown the air
compressor. 4. TROUBLESHOOTING to the
specified value for each type of air compressor
Section 9)
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