A compressed air leak cannot be seen, leaves no mess and can barely be heard over the noise of the workshop. Yet every leak forces the compressor to produce air that serves no purpose. That is electricity paid for to heat the workshop and wear the machine out faster.
The warning signs
- The compressor restarts when nobody is using air, in the evening or at the weekend.
- The compressor runs more often than before, although activity has not changed.
- Pressure drops at the end of the network when several workstations are working.
- You hear a hissing sound near fittings once the machines are switched off.
The simplest test - the workshop at rest
- At the end of the day, switch off all tools but leave the network under pressure.
- Let the compressor build up pressure and stop.
- Note how long it stays off before restarting, then how long it runs to build pressure back up.
If it restarts while nothing is being used, air is escaping somewhere. The longer the running time compared with the off time, the bigger the leaks. Repeat this test after repairs to measure the improvement.
Where to look first
Leaks are almost always concentrated in the same places:
- Quick couplings: worn seals, couplers damaged by being dropped.
- Hoses: cracks, crushing, poorly tightened clamps.
- Filters, regulators and lubricators: tired bowls and seals.
- Drains: manual drains not closed properly, automatic drains stuck open.
- Threaded fittings on the fixed network, especially at vibration points.
- The tools themselves: worn triggers and internal seals.
How to locate a leak
By ear
In a quiet workshop in the evening, large leaks can be heard. Walk along the network slowly, fitting by fitting.
With soapy water
Apply soapy water with a brush or spray bottle to suspect fittings: the leak forms bubbles. Simple, free and very effective on small leaks.
With an ultrasonic detector
For a large network or a noisy workshop, an ultrasonic detector picks up the hiss of leaks, even when it cannot be heard by ear. Service providers offer this type of leak detection campaign.
Repair, then tag
- Replace worn seals and couplers rather than tightening them.
- Change cracked hoses: a repaired hose often leaks again.
- Reseal threaded fittings with a product suited to compressed air.
- Mark each leak with a tag during the search, and remove it once repaired: nothing gets forgotten.
Stopping leaks from coming back
- Isolate unused areas with a valve, and shut off the air supply in the evening when possible.
- Do not set the pressure higher than necessary: the higher the pressure, the more air a leak lets out. Our article Bar and pressure - how to calculate the pressure you need explains how to get it right.
- Carry out the workshop-at-rest test regularly, for example once a quarter.
- Choose quality fittings and hoses, suited to the network pressure.
Our connection hoses and pressure gauges are available from stock in France. One pressure gauge at the compressor outlet and another at the end of the network are enough to monitor the condition of your installation day to day.