During our latest test of vacuum reflow solder unit VSU28-D we measured heating rates of up to 996 K/minute. We ran this test without software limitation on the ramp speed and in maximum power. In 118 seconds the chamber reached 800°C. The experiment is made in 100mbar vacuum with the standard blank graphite plate 260x210x4.5mm and 230V supply. This power test shows that the dual heating VSU28 can be used for rapid thermal annealing of substrates or in any other cases where fast heating is required.