It is taking time to adjust to different way of working compared to our other De Longhi heaters. On those we set a therm dial to a level to start; the heater then switches on/off at that level. We tried that on the vonhaus but the heater went cold when it clicked off.
OK , then read the instructions more carefully: set the dial high, when room feels warm enough turn dial down slowly till there's a click and light goes off. But that is as at a level of the heater's choosing, not ours! Not sure if we can adjust the warmth we need from then on by turning dial up or down. 
Surprised to find that pushing power buttons fully in does not turn heater off. Have to pull plug out every time.
Good news? Yes, it works and warms up quite quickly.
Richard