Troubleshooting - SMC Networks VEX5 Series Operation Manual

Troubleshooting

Perform troubleshooting with higher possibility based on the failure phenomenon.
Failure phenomenon
Operation failure
Sealing failure
Buzzing noise
Pressure cannot be
adjusted
The pilot valve can not switch.
The pilot valve switches, but
the poppet valve does not, or
there is a delay in switching.
Coil burnout.
Air leaks from the poppet valve.
Air leaks from the pilot exhaust.
Air leakage at connected part.
When the power is supplied,
a loud buzzing sound is
continuously generated.
The pressure does not
increase even if the signal
pressure is increased.
The set pressure fluctuates
even though the equipment
on the secondary side has
not been operated.
Possible causes
Incorrect voltage.
Incorrect wiring.
Fuse blown out, breakage of lead wire.
Incorrect contact at the contact and connection.
Open coil wire.
Foreign matter is caught in the armature.
Pilot pressure is decreased.
Swelling of the valve seal and piston seal.
Excessive oil supply.
Voltage is too high. Or incorrect coil.
Directly exposed to water.
Wearing of the valve seal / the piston seal.
Foreign matter is caught in the poppet.
The poppet valve is not completely switched.
Sealing failure of the driving device.
Increase of the pilot pressure.
Foreign matter is caught in the seat.
Foreign matter is caught in the armature.
Loosening of the bolt.
Wear of the armature.
Foreign matter is caught in the armature.
Decline in the power supply voltage.
AC voltage is applied to the DC pilot valve.
Insufficient supply pressure and pilot pressure
Air is consumed by the equipment on the
secondary side.
Or, air leaks from the piping on the
secondary side.
Foreign matter is caught in the poppet
valve on the exhaust side.
The seal has swelled, and the supply
poppet valve does not switch.
The supply pressure fluctuates.
The pilot pressure fluctuates.
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Countermeasures
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No.VEX∗∗∗∗-OMA0019-C