What does start T (A) mean on a Kaeser Sigma Control?
Short answer: Too cold to start. If your Kaeser Sigma Control (original) is showing start T (A), 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 airend discharge temperature is too low to allow the package to start; the ambient temperature must be higher than +3°C.
Which machines show this?
first-generation Kaeser rotary screw compressors fitted with the original Sigma Control — the green-keypad, text-display controller Kaeser introduced around the turn of the 2000s on its direct-drive screw packages. This controller shows faults as short lower-case text messages with a severity letter: (A) for an alarm that shuts the machine down, (W) for a warning it keeps running through — so 'ADT (A)' is an airend-temperature shutdown while 'separator dp (W)' is a clogging separator flagged early. Alarms are acknowledged with the reset key after the cause is fixed. Practical tip: these machines also enforce a minimum start temperature of +3 °C, so a winter no-start in an unheated room is often the controller doing its job, not a fault.
What causes it?
- Ambient below +3°C — the airend is too cold for the package to start
- An unheated compressor room in winter
Can you fix it yourself?
Yes — warm the room above +3°C and avoid forced start attempts in the cold.
Step by step — what to try, in order:
- Warm the compressor room above +3°C before attempting a start.
- Avoid repeated forced start attempts in the cold.
When do you need a technician — and why?
A room that routinely drops below +3°C needs an auxiliary heating system specified through Kaeser service; repeated cold-start attempts are the expensive alternative.
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 start T (A) mean on a Kaeser Sigma Control (original)?
Too cold to start. The airend discharge temperature is too low to allow the package to start; the ambient temperature must be higher than +3°C.
Can I fix start T (A) on a Kaeser Sigma Control (original) myself?
Yes — warm the room above +3°C and avoid forced start attempts in the cold.
When does start T (A) on a Kaeser Sigma Control (original) need a technician?
A room that routinely drops below +3°C needs an auxiliary heating system specified through Kaeser service; repeated cold-start attempts are the expensive alternative. If the room routinely drops below +3°C, ask Kaeser service about fitting an auxiliary heating system.
Verified against service documentation: Kaeser Sigma Control (original) documentation for start T (A) (airsolcan.com)