I used to have a Millermatic 35 and I remember the fan coming on as soon as I powered it up. I just replaced it with a Millermatic 250. I love the welder but the fan does not come on when I start it. I took the cover off and with it running spun the fan by hand and it turned freely. So there is no power to it. Does anyone know if that model runs the fan all the time or only when it gets hot