This Technical Specification specifies basic requirements for thermal cycler performance and maintenance. Although thermal cyclers are robust technical equipment, they do require regular maintenance. Their cooling/heating elements, either Peltier or other technology, have a limited lifetime. Functionality of the cooling/heating element depends both on the quality of heating- /cooling devices and a proper use and care. Furthermore, this standard comprises precautions which should be taken for maintenance during routine use. Suggestions are made how to determine the performance of thermal cyclers either biochemically or physically.