If it is set at 5 that is equivalent to about 35% humidity. So if the current humidity level is higher than that it would not be running. An easy way to tell is to turn the unit to test reset (turn it past 7 and the humidifier on light should begin to blink with our 58-60 control) This should turn the humidifer on and it will run for approximately one minute. If this happens the unit is functioning normally and then when you turn it back to 5 it should come on , if the HVAC is running and the humidity falls below 35%.