I had the same problem with my Whirlpool oven as the post below. I replaced the thermostat at a cost of 35 UKP from keepingupappliances.com. The thermostat is connected into the rear of the oven. An easy change removing about 10 screws. Took about half an hour. Thought I would post this as I couln't find any followup answer to the original thread. All working well now. Wife is off my back...
We were wondering if anyone could tell us how hard it would be to
>replace a thermostat on a Whirlpool AKP510 electric oven, more
>importantly where the thermostat is located. The problem with the oven
>is that it doesn't heat up. When we switch it on at 250F the power
>light comes on but if we turn it down to 220F the power light goes
>out, even if we leave it running at 250F it doesn;t heat up properly.
>We have sourced a spare themostat from CPC for 30 pounds.