Hello! I have built an electric furnace using an Auber Instruments PID temperature controller and an AC contactor. I have been testing it using a K-type thermocouple. I have run into a problem: I will program the controller to ramp to 1832 F from 50 F over 90 minutes, hold at 1832 F for 15 minutes, then turn off. The furnace only gets up to about 1525 F before the controller switches to "stop" mode and the program ends. Any idea what I'm doing wrong? Is there a parameter that I should change in the settings?