What does Kaeser alarm 0043 A (airend temp rising too fast) mean?
Short answer: Airend temperature rising too fast. If your Kaeser Sigma Control 2 is showing 0043 A — Airend discharge temperature ADT rise dT/dt ⇞, 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 permissible rate of rise of the airend discharge temperature was exceeded. Frequently points to low cooling oil or interrupted oil circulation.
Which machines show this?
the wide range of current-generation Kaeser rotary screw compressors — ASD, BSD, CSD, DSD, ESD and related series — built since roughly 2011 with the Sigma Control 2, the industrial-PC controller with a text display and RFID access. It reports faults as a four-digit number plus a letter: 'A' messages are alarms that shut the machine down, 'W' messages are warnings or service reminders it keeps running through, with arrows marking whether the value went over or under its limit — so 0015 A is the airend-overheat shutdown while 0013 W just asks for an air filter. Practical tip: the same subsystem often has a W and an A code (0004 W before 0022 A on the separator); acting on the W message is how you avoid the A shutdown.
What causes it?
- Cooling oil level low — the most common driver of a fast temperature rise
- Oil circulation interrupted
- Ambient temperature or ventilation problems
Can you fix it yourself?
Sometimes — checking and topping up the cooling oil and correcting ventilation is in-house; a correct oil level with the alarm returning is not.
Step by step — what to try, in order:
- Shut down safely and let the unit cool.
- Check the cooling oil level and top up with the approved fluid if low.
- Check ambient temperature and ventilation.
When do you need a technician — and why?
Interrupted oil circulation or a faulty temperature sensor needs professional diagnosis — a screw compressor running with broken oil flow destroys itself quickly.
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 0043 A — Airend discharge temperature ADT rise dT/dt ⇞ mean on a Kaeser Sigma Control 2?
Airend temperature rising too fast. The permissible rate of rise of the airend discharge temperature was exceeded. Frequently points to low cooling oil or interrupted oil circulation.
Can I fix 0043 A — Airend discharge temperature ADT rise dT/dt ⇞ on a Kaeser Sigma Control 2 myself?
Sometimes — checking and topping up the cooling oil and correcting ventilation is in-house; a correct oil level with the alarm returning is not.
When does 0043 A — Airend discharge temperature ADT rise dT/dt ⇞ on a Kaeser Sigma Control 2 need a technician?
Interrupted oil circulation or a faulty temperature sensor needs professional diagnosis — a screw compressor running with broken oil flow destroys itself quickly. If oil level is correct and the alarm returns, call service — oil circulation or the temperature sensor needs professional diagnosis.
Verified against service documentation: Kaeser Sigma Control 2 documentation for 0043 A — Airend discharge temperature ADT rise dT/dt ⇞ (airsolcan.com)