Troubleshooting / Compressed air system

Compressed Air System Troubleshooting

The most common compressed air system problems on the plant floor, with the likely causes and the fix for each. Part of the OEE Lab troubleshooting directory.

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Problems on this page:

Pressure drops at peak demandHigh leakage across the plantPressure set higher than neededWater, oil or particles at the point of useCompressors working against each otherRust and scale in the pipesCompressed air used where it is not neededDrains wasting air or not drainingAir receiver problems

Pressure drops at peak demand

Hits OEE: Performance

Symptoms: Pressure falls in the plant during busy periods and machines fault on low air.

Compressor capacity below peak demand
Measure demand over a full production day.
Compressor control set points
Check the load and unload pressures.
Receiver storage too small
Add storage near large intermittent users.
Leaks adding to the demand
Run a leak survey.

Prevention: Plant pressure logged and reviewed weekly.

High leakage across the plant

Hits OEE: Performance

Symptoms: Compressors run on weekends and nights with no production.

Leaks never surveyed
Survey with an ultrasonic detector and fix in order of size.
Old fittings and hoses
Replace aged parts.
Machines left pressurised when idle
Isolate machines when they stop.

Prevention: Non-production compressor load measured regularly.

Pressure set higher than needed

Hits OEE: Performance

Symptoms: The system runs at high pressure to keep one user working.

Pressure drop in the network
Find and fix the drop instead of raising pressure.
One user needs higher pressure
Give that user a local booster.
Set points never reviewed
Review the set points.

Prevention: Set points reviewed when users change.

Water, oil or particles at the point of use

Hits OEE: Quality

Symptoms: Contaminated air at machines, failing valves, product contamination risk.

Dryer not working
Check the dryer.
Filters loaded or bypassed
Change the filters and close any bypass.
Drains failing
Test the drains.
Corroded pipework
Inspect the pipework.

Prevention: Air quality checked at critical users.

Compressors working against each other

Hits OEE: Performance

Symptoms: Several compressors load and unload in turn and energy use is high.

No sequencing control
Use a sequencer or a master control.
Overlapping pressure bands
Set the pressure bands so they do not overlap.
Variable-speed compressor not used as the trim unit
Let the variable-speed unit trim the demand.

Prevention: Compressor running hours compared monthly.

Rust and scale in the pipes

Hits OEE: Quality

Symptoms: Rust in filters and valves, blocked small passages.

Wet air in steel pipe
Dry the air and consider corrosion-resistant pipe.
Low points without drains
Fit drains at low points.
Old pipework never flushed
Flush or replace the pipework.

Prevention: Filter elements checked for rust at changes.

Compressed air used where it is not needed

Hits OEE: Performance

Symptoms: Open blowing, cooling or cleaning with compressed air all shift long.

Open pipes used for blowing
Fit engineered nozzles.
Air used for cooling or drying
Use blowers or fans where possible.
Air left on when the machine stops
Add valves that shut off with the machine.

Prevention: Air uses reviewed during energy audits.

Drains wasting air or not draining

Hits OEE: Performance

Symptoms: Drains hiss all the time, or water builds up in receivers.

Timer drains set too long
Shorten the open time or use level-sensing drains.
Level-sensing drain failed
Test and repair the drain.
Drain strainer blocked
Clean the strainer.

Prevention: Drains tested on the route.

Air receiver problems

Hits OEE: Availability

Symptoms: The receiver fills with water, shows rust, or its safety valve lifts.

Receiver drain failed
Repair the drain and check it on the route.
Inspections overdue
Inspect the receiver as the pressure equipment rules in your country require.
Safety valve never tested
Have the safety valve tested by a competent person.
Pressure switch set too close to the safety valve
Check the compressor and switch settings.

Prevention: Receiver inspections and safety valve tests on a written schedule.

Guidance only. Always follow lockout/tagout and your site's safe-work procedures, and verify against OEM manuals before acting.

Related equipment guides: air compressor · compressed air dryer · pneumatic system · solenoid valve · vacuum pump · nitrogen generator · pneumatic conveying system · transformer · optical sorter · EPS moulding machine · air-operated diaphragm pump · pressure transmitter · wine press · leak tester

Stop the same fault coming back

Recurring compressed air system stops usually trace to a cause you cannot see by hand. The partner we recommend is Fabrico: it tracks OEE and downtime live from PLCs, IoT sensors or AI cameras; where cameras are fitted, the video of a stop sits next to its machine data so the cause can be reviewed; and a technician opens the work order from the stop in the same system. Data is hosted in the AWS EU region, and Fabrico and the company behind it hold ISO/IEC 27001, ISO/IEC 20000-1 and ISO 9001.

Book a Fabrico demo
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Related tools: full troubleshooting directory · OEE calculator · downtime cost · MTBF / MTTR · glossary

Methods that cut recurring stops: the six big losses · root cause analysis · preventive vs predictive maintenance · TPM · SMED & changeover