GE gas oven wont turn off JGBS23BEA2WH

[D Armstrong]

20 year old gas oven, there is only one burner/ignitor/valve for bake and broil.  The oven would not turn off while the temp selector was in the "off" position (has a positive stop, click sound/position).  I checked the controller for continuity in the off position and had zero resistance.     Since the oven temp had been off for quite a while, i replaced the temp control thermostat.  I verified resistance on the new part before installing.  I baked for four hours, temp was perfect then turned the oven off.  Two hours later i noticed the oven was warm and that it was on.  I disassembled again and checked the thermostat control, it now had full continuity in the off/open position.  The gas valve was replaced about six years ago, and the ignitor has been replaced several times, maybe three years since the last.  I checked all the wiring for breaks/ burns/mouse chews/etc and found nothing.  Anyone have this problem or an idea as to what the problem might be?  Thanks

[MA tech.]

Verify your measurements. If you are reading a closed circuit through the thermostat, While the thermostat is in the off position? then nit is a bad thermostat. It should say open. What is the voltage at the safety valve. ? Is the igniter glowing when the thermostat is off?

[Budget Appliance Repair]

Did you purchase the oven t-stat new and was the part# you ordered and received WB20K8?

The
Part number: WB20K8

is the open frame style t-stat that you can see the shaft cam and switch plunger, these are generally pretty reliable oven t-stat new, (they do wear out and go out of calibration after many years usually).

You could have been sold a WB20K10023 oven t-stat that would work mechanically and physically as a direct replacement.  It is the black box style and I've seen many of these fail.

Regardless is sounds like you got a BAD new oven t-stat and hopefully you purchased from RepairClinic or Appliance Parts Pro's on this site where you will have no problem getting it replaced.