What are the definitions of working temperature range and operating temperature range or ACC range?
Working temperature range and operating temperature range are concepts defined in the DIN 58966 standard, part 1. The working temperature range is defined there as the temperature range reached at an ambient temperature of 20°C by the circulator alone, using only the specified energy sources and not using any additional devices. In practice the energy source is nearly always electrical energy. In a heating circulator the working temperature range starts approximately 3°C above the so-called intrinsic temperature and in most cases ends at the upper limit of the operating temperature. The intrinsic temperature is produced when the heating is switched off, due to the mechanical energy input, and it depends on the pump output, the insulation of the circulator, and the bath liquid used. If, for example, the bath cover is not included in the standard accessories, the upper limit of the working temperature range is restricted to the operating temperature, which can be reached by the circulato
