Hi,
The Harvard Science and Cooking Course has a effective way to calibrate using a phase change on sugar which melts at 366F. I followed this with a verification of the cycle my oven.
Phase Change Calibration:
Code:
1) Preheat your oven to 350F (177˚C).
(2) Place the granulated sugar in an oven proof dish or on aluminum foil
(3) Place in oven for 15 minutes
(4) If the sugar doesn't melt, raise the temperature of the oven by 10F (5˚C) and repeat the experiment.
I found my oven running hot by 15 degrees. I also found slight melting a the lowest temp after leaving the sugar in the oven.
The oven probe documented a 23 degree cycle over time. I then talked to my repair shop who said that cycles varied up to 25 degrees. They also mentioned that some new ovens have very low cycle changes.
Tim