Common air compressor problems and their repairs vary depending on the type of compressor. For example, a common problem with a rotary screw compressor is that it refuses to start. To repair this problem, check the power supply to the compressor and reset its overload relay.
Rotary screw air compressors, like other types, have common issues owners should be aware of. If the compressor shuts down in high temperatures, check to make sure it has enough of the right type of oil. Check the thermostatic valve to be sure it is working properly, and make sure there is no debris in the oil lines.
If water appears in the compressed air, understand that, to a degree, this is normal. However, if there is too much water coming from the rotary screw compressor, check the dew point.
Reciprocating air compressors sometimes make odd noises when there is an oil leak or when the compressor has a high oil carryover. Repairing this problem requires making sure the oil level is not too high and that the right kind of oil is in the machine. Check the cylinder surface and piston rings to be sure they are not badly worn.
Portable air compressors that refuse to start may have the safety switch engaged. If the compressor does not load, try checking the loading valve to make sure it opens. If the engine does not rev up, check for a dirty air filter and replace if necessary. Clean the exhaust system and check the speed controller.