Troubleshooting Chart for Air Compressors

April 25, 2015

While the basic working principle of any air compressor can be the same, the design of ach equipment is different from manufacturer to manufacturer and from one model to another. One of the best places to refer for repair and service of your air compressor is the owner’s manual.

This article is a troubleshooting guide that gives a list of most common air compressor problems in general, with their possible causes and some remedies to fix the issues. This is not an alternative to the manufacturer’s guide but an additional source to be used as a complementary reference guide along with the owner’s manual.

Before making any purchase of any spare parts, always refer to owner’s manual in order to make sure that the right parts are purchased.

Problem/Symptom	Possible Cause	Recommended Solution
Compressor not starting.	No electrical power.	Turn on power. Push the reset button.
	Low oil level.	Check oil level. Replace your oil if necessary
	Pressure switch not making contact.	See pressure switch adjustment.
	Pressure in the tank is below the cut-in pressure.	See pressure switch adjustment. Replace pressure switch to one that has a lower cut-in PSI
Excessive Vibration during operation	Loose fasteners or mounting bolts loose.	Tighten all fasteners properly
	Improper installation	Check leveling and make sure that all feet touch the floor before tightening the foundation bolts.
	Compressor Not aligned properly.	Recheck the pulley and flywheel alignment. Realign the compressor
	Loose pulley or belts	Tighten
	Compressor floor mounting loose.	Tighten the mounting bolts.  Check and replace anti-vibration pads if necessary.
High discharge air temperature.	Inadequate ventilation in compressor room.	Improve ventilation or relocate compressor.
	Restriction in the air intake.	Check, Clean or replace the intake air filters.
	Broken/ defective head gasket.	Check and replace the gasket.
	Poor Cooling system  or clogged cooling surfaces.	Check and adjust the cooling system/ water supply. Clean cooling surfaces of cylinder, intercooler, after cooler  and discharge pipe.
Knock – that occurs at same interval as the compressor rotation (rpm)	Defective main bearings.	Check and replace bearings.
	Defective Connecting rod bearings.	Check and replace rod bearings or the rod itself
	Flywheel is loose on the shaft	Check and tighten properly.
Knock – that occurs when the compressor is loading.	Defective Connecting rod bearings.	Replace.
	Defective Wrist pins, wrist pin bearings.	Check and Replace piston assembly.
	Loose connecting rod nut.	Tighten properly.
Oil discoloration (milky while oil in the oil chamber)	Water (excessive Moisture) entering the oil chamber.	Re direct the air intake pipe  to less humid air source if possible.
		Change oil more frequently( appx 500 hours). Clean or replace air cleaner elements more often.
Oil particles coming with the discharge air.	Restriction in the air intake.	Check, Clean or replace you’re the intake air filters.
	Excessive oil in the oil chamber..	Check and drain out extra oil. Never go over the max level in sight glass..
	Wrong oil grade or viscosity.	Check the oil grade or viscosity and replace if needed.(remember to use the right grade of oil all the time)
	Piston rings installed up-side down.	Check and Replace.
	Worn piston rings.	Check and Replace rings (or piston assembly).
Too much oil consumption.	Restriction in the air intake.	Check, Clean or replace you’re the intake air filters.
	Oil leakage.	Check and replace gasket.
	Wrong oil grade or viscosity.	Check the oil grade or viscosity and replace if needed.
	Compressor not level (too much tilted).	Level the compressor. Use Anti-Vibration pads in necessary
	Worn piston rings.	Check and Replace rings (or piston assembly).
Power supply fuses blow repeatedly.	Wrong fuse size.	Check and verify that fuses are of proper ampere rating.
	Motor Overload	Stop the compressor immediately check thoroughly for overload reasons. Overload could happen due to various reasons that could be mechanical or electrical. Call Electrician to check the power system and the motor.
Low  pressure at point the of use.	Air Leaks or restriction in discharge piping.	Check for air  leaks or restriction in discharge piping. Repair/replace as needed.
	Restriction in the air intake.	Check, Clean or replace you’re the intake air filters.
	Slippage on belts.	Tighten the belts.
	Too small size of hose/pipe at the point of use	Replace with larger pipe or hose.
	Increased air requirement.	Limit air usage to compressor capacity. Use additional compressors if needed. Consider reducing consumption by using fewer or smaller tools.
Receiver not holding  air pressure once the compressor is unloaded.	Defective check valve. Or check valve not closing properly.	Release pressure from the receiver tank, Disassemble check valve assembly, inspect the valve seat, clean or replace faulty parts. Replace complete valve assembly if parts not available.
Belt wearing too fast	Misalignment.	Check and realign the motor pulley with compressor flywheel.
	Belts over tightened	Check and adjust tension.
	Belts too loose.	Check and adjust tension.
	Wobbling in pulley or flywheel	Check for loose key/key ways or Pulley. Inspect for crankshaft wear out or bend. Replace items as needed.
	Rough surface on belt pulley grooves.	Check and file smooth, or replace as needed.