cgarner

This makes me think your dial is a little off set. Is there a position between "Off" and 11 o'clock where it is actually off? (No buzzing or clicking or heating.) Kiln controllers only shut the elements on or off, they can't turn the current down. Low settings have more off time and less on time, as you have measured above. This makes me think your dial is working, it is just twisted a bit compared to the markings. 4 hour firing is mighty fast but could work. Most of my stuff would blow up if it was green ware and didn't candle it for half a day first. You should be able to control it better than this, and not by opening the lid!