Where water appears
Typical locations are the aftercooler, separator, air receiver, filters and dryer. If treatment is inadequate for operating conditions, condensation continues into the distribution system. Draining the receiver alone does not guarantee dry air at the consumer, as vapour may remain in the flow.
Separate, drain, treat
Different devices perform these steps. A separator separates droplets from the air, a drain discharges them from the pressurised space, and a condensate separator treats the liquid already drained. Removing water vapour requires a suitable dryer.
What to check in practice
- Check drainage at every point where liquid collects.
- Include summer intake conditions and maximum flow in capacity sizing.
- Collect and manage the drained liquid according to its composition, not just its appearance.
Example scenario
In an illustrative balance, the intake brings in 8 kg of water per hour and 2 kg/h remains in the outlet air. At steady state, approximately 6 kg/h, or about 6 L/h, is separated. Define the points between which the balance applies to avoid counting the same water twice.
What to watch out for
- Automatically treating water in the pipework as an airend fault.
- Discharging oil-contaminated condensate without assessing its treatment.
- Setting drain timers based on only one season.
Does condensate also form with an oil-free compressor?
Yes. Oil-free compression does not remove moisture from the intake air. The possible composition of contaminants differs, but water still needs to be separated, drained and monitored.