Hello everyone, I have a Dacor raised ventilation unit Model No: RB46 that has 6 control buttons on the top right corner. The up/down button works where the unit will raise up and the fan will start on high. The high & off buttons also works but the medium, low and filter reminder buttons do not work. If you press the timer button, the fan will slow to the medium speed. Does anyone know how I can check this out to see if there is a bad switch or a faulty control board?