Water in the compressed air — dryers, drains and frozen lines
Symptom
Water in FRL bowls every day, valves stick in the morning, outdoor lines freeze in winter, or cement lumps form at the silo aeration pads.
Likely causes
- Dryer switched off, bypassed or failed.
- Condensate drains blocked or left closed.
- A refrigerated dryer (dew point about +3 °C) on outdoor lines that get colder than that.
- Filter bowls not drained before water reaches the baffle.
Most likely and cheapest to check first.
Checks
- Read the dryer dew point display; check its condenser fins are clean.
- Press the test button on every automatic drain; open manual drains daily.
- Compare the lowest outdoor temperature with the dryer dew point.
Fix
- Repair the dryer and drains; never bypass the dryer.
- Fit a desiccant dryer, or insulate and heat-trace outdoor lines in cold climates.
- Change line filter elements at least yearly and service drains yearly.
- Clean or replace caked aeration pads (Book 2).
Parts you may need
A failed drain sends water down the line
Valves stick, cylinder seals swell, silo aeration pads cake with cement, and in winter the lines freeze. Condensate from oil-injected compressors contains oil: dispose of it through an oil-water separator, not into a drain.
FIELD TIPDrains are the most forgotten part of the air system. Put "press every drain test button" on the daily checklist.
⚠ Every check inside a machine starts with full lockout. Safety disclaimer