Air Compressor Fault Codes Explained

Six or seven out of ten service calls are this fault. Temperature alarm threshold varies by brand. Atlas Copco GA series defaults to 221°F. Fusheng SA series 212°F. Ingersoll Rand most models set at 230°F. Exceeds this value, controller shuts down for protection.

Vast majority of cases, problem is in oil cooler. Fins caked with dust causes heat exchange efficiency to drop. Textile mills, cement plants, flour mills, these heavy dust environments especially bad. Some plants go two months without cleaning fins and report high temperature. Fix is simple. Remove cooler housing, use compressed air to blow in reverse direction. Ingersoll Rand fins have small spacing, keep air pressure below 45 psi. Too high pressure bends the fins, makes it worse. Internal oil passages with scale need to be removed and soaked with circulating cleaner.

Oil level insufficient ranks second. Many times not a leak, but return oil line blocked. Oil accumulates in separator tank, oil level on airend side slowly drops. So when you see low oil level, don’t rush to add oil. Check return oil line first. Sensor failure probability actually not high, but have encountered it. Test method is use infrared thermometer gun on discharge pipe surface, compare with controller display value. Deviation exceeds 15°F, basically can confirm sensor drift. PT100 type sensor can be removed and resistance measured. 212°F corresponds to about 138.5Ω.

This fault most of the time is not compressor’s problem. Downstream air-using equipment suddenly stopped. Air in pipe network has nowhere to go. Pressure spikes instantly and triggers alarm. VFD machine responds fast but still takes a few seconds. Compressor’s own problem mainly look at minimum pressure valve. Valve core and valve seat have oil sludge between them, or spring fatigued, both cause opening pressure to rise. Air can’t get out, pressure goes up. Sullair minimum pressure valve spring tends to be soft.

E003 needs to be judged together with load indicator light. Load light on but pressure won’t come up, problem is at inlet side. Most common is inlet valve not fully open. Fusheng butterfly-type inlet valve uses servo cylinder to push. Seal ring aged and leaks, then valve plate can’t reach position. Atlas Copco uses solenoid valve to control inlet valve. Also air filter blocked. Textile mill air filters need changing every two or three months. Remove filter element and run unloaded to test. If pressure returns to normal, it’s the air filter.

First measure voltage. Three-phase voltage should be within ±5% of rated value. Many industrial parks during daytime peak usage, voltage drops below 360V. Motor to maintain power output, current has to rise. Recommend installing voltmeter in control cabinet so you can see anytime. Voltage no problem, then look at pressure setting. Discharge pressure adjusted from 115 psi to 145 psi, 30 hp model current increases about 15%.

Mechanical causes include airend bearing wear, rotor clearance enlarged, insufficient lube oil causing increased friction. Before barring to check if it turns smoothly, first confirm separator tank is depressurized. Barring under pressure has caused accidents. Carrier screw machines have one easy pitfall. Y-delta switching timer setting wrong. Switching moment current impact triggers protection. Generally set to switch 8 to 12 seconds after startup is appropriate.

E005 related to E004. Motor running at overload edge long-term, temperature rise definitely high. Ambient temperature exceeds 104°F, motor cooling capacity noticeably drops. Northern summer midday, machine room temperature often 113°F and up. Motor housing dust accumulation affects heat dissipation. Blow it clean, can drop 10-15°F. Bearing temperature can be measured with infrared thermometer gun through end cover vent holes. Normal doesn’t exceed 160°F. Noticeably hot, time to change bearings. VFD motors have special situation. Low frequency operation, self-cooling fan speed drops, cooling capacity decreases.

Differential setpoint usually 12-15 psi. Exceeds this means separator element needs changing. Separator element normal life 3,000 to 4,000 hours. Humid environments or poor oil quality shortens to 2,000 hours. After differential alarm, continuing to run sick isn’t worth it. Every 1.5 psi increase in differential uses about 1% more electricity. Buying separator element pay attention to model. Sullair and Atlas Copco specs aren’t interchangeable. Return oil line blockage also causes high differential. This line has only 1/8 inch ID. Inside also has orifice. Oil sludge easily blocks it. Remove and poke through with thin wire.

E007: Start with simple stuff. Is emergency stop button popped out? Is control cabinet door closed? Some models won’t start with door open. Is power indicator on? These low-level issues can screen out 30% of service calls. Power phase loss, use multimeter to measure three-phase voltage. One phase noticeably low or zero, that’s phase loss. Separator tank residual pressure too high, startup load heavy, star-delta switching current impact triggers protection. Few minutes later drops to below 30 psi. Blowoff valve solenoid stuck or bleed hole blocked, residual pressure can’t bleed.

Controller will display which specific sensor has problem. Temperature sensor and pressure sensor fail most easily. But before replacing sensor, first tighten all wire terminals. Compressor vibration is heavy. Loose wiring causing unstable signal is quite common. Tightened and fault disappears, also common. Pressure sensor diaphragm damaged causes signal drift. Connect a standard pressure gauge to compare. PT100 temperature sensor measure resistance. Control board failure probability low. Only consider after sensors and wiring both ruled out.

E010 must look at secondary code displayed on VFD panel. Different brands define completely differently. ABB overcurrent shows F0001. Siemens shows F0021. Emerson shows OC. Overcurrent, check motor insulation, check if output cable is shorted, check if motor parameters set correctly. Overvoltage or undervoltage is input power issue. Overheating, check if VFD cooling fan is turning, is filter screen blocked, is installation location ventilation good.

Communication interrupt means controller can’t read VFD status. Check communication wire and terminals for oxidation. RS485 communication wiring has polarity requirement. A to A, B to B. Connected backwards, won’t communicate. VFD power module damaged is major repair. Usually send out for repair or replace. IGBT breakdown can be tested with multimeter diode mode.