AirCompDX

Diagnose

Pick a symptom — get likely causes, checks, and fixes.

New
Master Troubleshooting Guide
System-by-system reference with safety rules and cheat-sheet values.

Won't run

Compressor will not startCompressor will not unload / stay unloadedRuns continuously, never cycles off standby

Electrical

Trips breaker or overloadWye-Delta starter problemContactor chattering or burningVSD (variable speed drive) faultMotor overload trips intermittently with no obvious cause

Pressure

Low discharge pressure / won't build pressureDischarge pressure too high / safety valve liftingShort cycling (loads/unloads rapidly)Long pump-up timeBlowdown/vent valve leaks air continuously after shutdownInlet/unloader valve stuck (open or closed)Minimum pressure valve / check valve not holding sump pressureSafety/relief valve pops or leaks at the seatAdequate tank/line pressure but low flow (CFM) at point of use

Temperature

High discharge temperatureAftercooler not cooling effectively

Controls

Controller / HMI shows fault but won't clearWon't transition between load and unloadController/PLC communication fault or lost networkMultiple compressors not sequencing correctly (lead/lag/trim)

Lubrication

Low oil pressure trip (screw)High oil consumption (reciprocating)Oil foaming or high oil consumption with foam visible in sight glassOil found in downstream air lines despite separator in good conditionOil leaking at motor/airend shaft seal or coupling area

Air quality

Oil in discharge air (rotary screw)Water in discharge airAir/oil separator element bypassing (high oil carryover with new element)Moisture found in instrument air system

Drain / condensate

Automatic drain not drainingElectronic condensate drain solenoid not opening or stuck openStanding water accumulating in receiver tank

Belts / drive

Belt squeal, slip, or premature failureCoupling or gearbox failure between motor and airendMotor bearing failure (noise, heat, or vibration at motor)

Air treatment

Refrigerated dryer dewpoint too highDesiccant dryer not switching towersRefrigerated dryer freezing up internally

Noise

Abnormal noise / vibrationElevated overall vibration readingLoud bang/thump at wye-to-delta transition on startWhining or grinding noise from gear drive (geared screw units)