Support

  1. General Malfunctions
  2. The general malfunctions/disturbances in pneumatic systems, their possible causes and rectification are listed below

    Disturbances Possible Causes Rectification
    Machine is working,
    but is weakening in performance
    due to slower operation
    • Upstream flow restriction or air starvation
    • Downstream flow restrictions
    • Lack of lubrication
    • Fit larger pipe
    • Install local reciever
    • Install larger compressor
    • Check twisted tube/blocked silencers downstream
    • Lubricate machines
    • Fit air-line lubricator
    One actuator is weakening
    in performance due to
    slower operation
    • Flow regulator set too low
    • Tube twisted
    • Lack of lubrication
    • Out of alignment
    • Object in actuator path
    • Piston rod bent
    • Barrel dented
    • Re-adjust flow regulator
    • Re-new
    • Fit air-line lubricator
    • Re-align
    • Repair or replace actuator
    Machine Stops
    • Failed pneumatic or electrical supply
    • Limit sensor moved out of position
    • Mechanical jam preventing an actuator
      from operating the limit switch
    • Re-establish power supplies
    • Adjust and tighten the sensor
    • Release the pressure from both sides
      of the actuator before clearing the jam
    Faulty products due to
    faulty machine adjustments
    or misalignment
    of components
    • Adjusting mechanism our of alignment
    • Limit sensor moved out of position
      causing short strokes
    • Failed ON sensor causing a skipped
      step in the sequence
    • Insufficient power to a stamping or
      pressing actuator
    • Re-adjust mechanism
    • Re-adjust limit sensor
    • Check arc suppressor circuit
    • Increase pressure to the actuator or
      replace the actuator with a large one
    Leakage
    • Loose joints, fittings or glands
    • Faulty or damaged fittings or
      ruptured pipes and hoses.
    • Tighten loose joints, fittings or glands
    • Replace or repair the defective part

  3. Malfunctions in Pneumatic Cylinder
  4. The frequently occuring malfunctions/disturbances in pneumatic cylinders, their possible causes, and rectification are listed below:

    Disturbances Possible Causes Rectification
    With valve connected, air
    escapes out of vent hole
    • (Double) cup packing is leaking
    • (Double) cup packing is loose (or valve
      is defective)
    • Replace cup packing
    • Tighten cup packing
    Air escapes to atmosphere at
    flange bushings
    • Cup packing is leaking
    • Cup packing is mounted in the
      wrong way.
    • Replace cup packing
    • Reverse cup packing
    Air escapes at piston
    End position cushion does
    not respond
    • Groove ring is defective.
    • Lip seal on the cushioning plunger
      leaks or has been fitted the wrong
      way round.
    • Fit a new grooving
    • Fit a new lip seal
    • Re-fit the lip seal
    Single-acting cylinder piston
    rod does not return to the
    end position
    • Compression spring is damaged.
    • Fit a new spring
    Misalignment of piston/
    piston rod or cylinder body
    • Excessive jerks
    • Wrong operation
    • Align piston/piston rod on cylinder body
    • Set right the operation

  5. Malfunctions in Pneumatic Valve
  6. Disturbances Possible Causes Rectification
    Valve leaks
    • Dirt
    • Scored seats
    • Broken seals
    • Groove ring damaged
    • Worn-out valve disc
    • Weak or broken spring
    • Deterioration of packing
    • Excessive wear
    • Remove dirt
    • Replace defective part
    • Replace seals
    • Replace groove ring
    • Replace defective part
    • Replace spring
    • Replace packing
    • Lubricate
    One actuator is weakening
    in performance due to
    slower operation
    • Flow regulator set too low
    • Tube twisted
    • Lack of lubrication
    • Out of alignment
    • Object in actuator path
    • Piston rod bent
    • Barrel dented
    • Re-adjust flow regulator
    • Re-new
    • Fit air-line lubricator
    • Re-align
    • Repair or replace actuator
    Valve operating
    mechanism fails
    • Line pressure too low
    • Binding action of the valve operating
      mechanism due to misalignment or lack of
      lubrication
    • Control plunger broken
    • Groove ring defective
    • Sticking spool due to swelling of seals
    • Burned-out coil
    • Broken lead to the coil
    • Broken parts such as connecting pins,
      lever arms
    • Corrosive damage to surfaces by condensate
    • Gumming due to lubricants without
      additives
    • Set control pressure
    • Align/lubricate
    • Replace plunger
    • Replace defective part
    • Replace defective part
    • Replace defective part
    • Replace defective part
    • Replace defective part
    • Replace defective part
    • Use proper lubricant
    Valve plunger does not
    return back
    • Look for broken spring
    • Replace defective part
    Spool does not reverse
    • Lumpy bearing surface, valve does not rest
      uniformly
    • Control pressure too low
    • Spool jammed
    • Second control signal cannot switch because
      first control signal still exists in memory
      valve
    • Flatten bearing surface
    • Set control pressure
    • Check sealing ring
    • Check tubing to the control
      ports
    • Clean the valve
    Sluggishness of valves
    • Dirt collected in the valve especially at the
      groove ring
    • A blocked vent hole
    • Clean the vent hole
    • Set right alignment
    Valve fails to pass the rated
    amount of air
    • Actuating means not stroking properly
    • Loosened cam
    • Bent trip cam
    • Worn tripping mechanism
    • Tighten cam
    • Straighten trip cam
    • Replace defective part
    The pneumatic output of
    solenoid valve is OFF
    when the relevant input
    device is activated
    • Electrical supply is OFF/Low voltage
    • Mechanical fault preventing the armature
      pulling-in
    • Burnt out coil
    • Failure of suppressor
    • Check the electrical supply
      back to the source
    • Rectify fault
    The pneumatic output is
    ON when the solenoid
    coil is de-energised
    Solenoid hums loudly
    • Manual override is left in the ON position
    • Solenoid plunger is not seating properly due
      to dirt
    • Replace coil
    • Repair the coil
    • Check and correct manual
      override
    Presence of arc at
    switching contacts
    Blown fuse of damaged
    switching circuit
    Failure of solenoid coil
    • Failure of arc suppressor fitted within the
      plug
    • Short circuit failure
    • Coil loosely fixed to the solenoid stem
    • Coil vibrates
    • Over-heating of coils
    • Mismatched coil and stem
    • Clean and set right
    • Check the suppressor
    • Check the suppressor
    • Fix coil firmly to solenoid
      stem
    • Use matched coils and stem