Which heater and electrical load are represented?
This entry is the 12 V diesel Thermo Top Evo 5 kW, not the petrol model or a complete vehicle heating system. The technical tables, pages 29 and 31, give 31 W at maximum heating for the heater and 14 W for the U4847econ coolant pump. The heater figure explicitly excludes both that pump and the vehicle blower. The catalog's 31 W / 12 V calculation therefore represents only the heater's nominal running load, not startup demand or total system current.