Why did the fan motor overload trip on my Atlas Copco compressor?
Short answer: Fan motor overload shutdown. If your Atlas Copco GA series (Elektronikon II regulator) is showing Overl Fanmotor (fan motor overload), the controller has logged a specific, documented condition. This page covers what it means, what causes it, what you can safely fix yourself, and when — and why — it takes a technician.
What exactly is the machine telling you?
The fan motor overload relay (F15) tripped and the Elektronikon stopped the compressor. The manual requires switching off the voltage, remedying the cause, and resetting the overload relay after it has cooled off before pressing Rset.
Which machines show this?
Atlas Copco GA-series oil-injected rotary screw compressors carrying the Elektronikon II regulator — the button-and-LCD controller generation that preceded the Mk 5 and Touch units, common on machines from the late 1990s and 2000s. Faults appear as plain-language messages such as *Shutd Warn* or *Serv Requir*, paired with the sensor name and the reading that caused them, and are cleared with the Rset key once the cause is gone. Warnings self-clear when the condition disappears; shutdowns latch until reset. Practical tip: the Status data menu tells you whether a service message came from a timer ('Plans') or a measured input like separator pressure drop ('Inputs') — check it before doing any work.
What causes it?
- Fan blocked or not spinning freely
- Heavy dust on the coolers making the fan motor work harder
- Overload relay F15 tripped hot and not yet cooled
- Fan motor, relay setting, or wiring fault if it keeps tripping
Can you fix it yourself?
Sometimes — if the fan was simply blocked or the coolers were filthy, clearing that and resetting F15 after cool-down fixes it.
Step by step — what to try, in order:
- Switch off and lock out the supply voltage
- Check that the fan spins freely and nothing is blocking the cooling air path
- Check for heavy dust buildup on the coolers making the fan work harder
- After cool-down, reset overload relay F15, switch voltage on, press Rset and restart
When do you need a technician — and why?
Resetting the relay means working in the electrical cabinet under lockout, and repeated trips need an electrician to measure the fan motor current and check the relay setting and wiring.
If it does come to a service call and you're in Nashville, TN or Birmingham, AL, we maintain independently compiled lists of local companies that service industrial air compressors — real businesses with verified contact information, none of whom paid to be listed.
Related questions
What does Overl Fanmotor (fan motor overload) mean on an Atlas Copco GA series (Elektronikon II regulator)?
Fan motor overload shutdown. The fan motor overload relay (F15) tripped and the Elektronikon stopped the compressor. The manual requires switching off the voltage, remedying the cause, and resetting the overload relay after it has cooled off before pressing Rset.
Can I fix Overl Fanmotor (fan motor overload) on an Atlas Copco GA series (Elektronikon II regulator) myself?
Sometimes — if the fan was simply blocked or the coolers were filthy, clearing that and resetting F15 after cool-down fixes it.
When does Overl Fanmotor (fan motor overload) on an Atlas Copco GA series (Elektronikon II regulator) need a technician?
Resetting the relay means working in the electrical cabinet under lockout, and repeated trips need an electrician to measure the fan motor current and check the relay setting and wiring. If the overload trips repeatedly, the fan motor, relay setting or wiring needs an electrician or authorized service technician.
Verified against service documentation: Atlas Copco GA series (Elektronikon II regulator) documentation for Overl Fanmotor (fan motor overload) (e-pneumatic.com)