[Stewie]

Unless you know exactly what you're doing it's silly to calibrate your oven. There are WAY too many variables. If you notice things have gone crazy (undercooked, overcooked) then don't waste your time, call a pro or buy a new oven.

Leave your oven alone, it was built to measure temperature and make adjustments. It's an on/off system so wide temperatures are a given and always have been.

Here are at least three issues (leave it to the pros that built your oven):

1) Never try to calibrate an empty oven, you'll **** it up.
2) What's the algorithm for cold junction compensation?
3) The oven is calibrated for its TC location, not some arbitrary location you choose.
4) Unless your oven was built before 1990, leave it alone.
5) Someone is trying to sell temperature measuring equipment and people bite.