Quick answers
What this page covers
Temperature problems rarely have a single cause. Goods, loading, door openings, outside temperature, cargo compartment condition, power supply and refrigeration often interact.
Typical signs
A problem usually becomes noticeable when temperature drops slowly, does not recover stably after door openings, or the system behaves differently while driving and stationary.
- The system runs but does not reliably reach the target range.
- Temperature rises significantly with frequent stops or high outside temperatures.
- The system behaves differently while stationary or on 230-V power than while driving.
- Fans, evaporator, condenser or airflow appear impaired.
Initial operational checks
Simple observations help before a technical diagnosis. They do not replace a workshop inspection, but make the service case much quicker to assess.
- Record setpoint, actual temperature and time.
- Document outside temperature, loading, pre-cooling and door openings.
- Check that the cargo compartment, air ducts and evaporator are unobstructed.
- Photograph the controller, rating plate, cargo compartment and visible abnormalities.
When Kerstner or a service partner should help
If temperature remains unstable despite correct operation, error codes appear or the system repeatedly shuts down, report the case systematically through the service team.
- Have the refrigeration system’s serial number and unit/equipment type ready.
- Add the VIN and registration number, if available.
- Describe how the fault develops over time, rather than simply writing “does not cool”.
- For warranty or goodwill claims, also prepare maintenance and handover records.
Relevant next steps
Frequently asked questions
Frequently asked questions on this topic
Why does my refrigerated vehicle not reach the set temperature?
Common causes include insufficient pre-cooling, frequent door openings, high outside temperatures, blocked airflow, incorrect loading, dirty components or a refrigeration fault. Temperature history, operating profile and photos help with assessment.
What should I check first?
Check setpoint, actual temperature, pre-cooling, door openings, loading and unobstructed airflow in the cargo compartment. Also note whether the problem occurs while driving, stationary or on 230-V power.
When should a service case be reported?
If the temperature is repeatedly not reached, error codes appear, the system shuts down or cold chain operation is at risk, report the case with vehicle details, unit type, serial number, fault description and photos.