With a measurement temperature range of 0 to +150°C and a measurement pressure range of 4000mbar the EBI 15 is a physical measuring system for checking steam sterilizers. This system can check relevant sterilization parameters such as vacuum, compensation time, hold time and sterilization temperature. The temperature inside a measuring chamber is compared with the outside temperature. If there is a temperature difference, then this is caused by insufficient steam penetration. On the basis of the temperature difference and of the behaviour of both temperature curves, a statement can be made regarding the cause of the insufficient steam penetration (leakage, insufficient vacuum, air injection). The software automatically evaluates the temperature difference during electronic readout and presents the results (where applicable) with cause of error.