alarm: fan M4 I high – trip

Questions & AnswersCategory: Generalalarm: fan M4 I high – trip
Guest Staff asked 6 months ago

recently one of the compressor got trip showing alarm showing – (fan M4 I high).

We refer manual and as per manual reset the machine and started it. It run fir a min, when going to second stage of starting motor (from idle to on load condition). It got trip again.

But inside the board there is no problem M4 contact didn’t trip. So we check the control panel to see if any relay problem inside the control panel. And found nothing. Can you please help me in troubleshooting the compressor. what should i check and how to do it.

other details
just changed oil filter and run only 50hrs
Oil sigma 570 run max 1000hrs

thanks in advances

1 Answers
Cas Staff answered 6 months ago


From the Kaeser manual I find that “fan M4 I” error means ‘Third fan motor shut down because
of overload’.

So form your question I understand that this happened the first time.. but now the alarm keeps coming back without M4 actually tripping? Right?

It sounds like there’s a bad contact in the M4 overload relay, or in the wiring or other parts in the alarm system.

But is suspect the overload relay more, because the problems started happening after it tripped once.

It’s hard to find.. because if you check afterwards with a multi-meter, often everything is fine.

If the contacts bounce open for only a few milliseconds, then it will already generate an alarm.

They could bounce open because the machine switches from unload to load and the makes the machine vibrate a little bit.

Overload relays are very susceptible to this kind of thing in my experience, especially when they have tripped before and are already some years old..

So please check that first.. if you get this alarm *every* time the machine starts, you can try to short-circuit the wires on the trip contact and see what happens. But you gotta be sure that the fan is OK, because you by-pass the overload safety. just try it for testing…

Hope this helps and love to hear how it works out!