Support

Support

General Malfunctions

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

Malfunctions in Pneumatic Cylinder

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

Malfunctions in Pneumatic Valve

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