JRP 15 oven showed 350F and gave preheat beeps. Frozen lasagna "cooked" 45 mins and was still almost frozen. Oven was warm inside, not hot. Bottom element glowed orange when I increased the temp setting to 400F, didn't help at all.

usually 40 minutes per 500 grams at 180 degrees C
so 1 and a half hours plus preheat the oven .
And it is thawed not frozen

don't just take my word for it read it on link below
http://www.pork.com.au/home-page-consumer/recipes/cooking-instructions.aspx

The bottom oven element is in need of replacement. Period.

Open the bottom and have a look at the burner while its heating. The flame should be strong blue/white and both sides the same, if they are not you have some blocked holes in the burner. Remove the burner and clean out the holes (carefully, don\'t ream them out, use a small paperclip to clean them, be gentle.). Above all do NOT use any kind of oven cleaner on them, if they are aluminum, and most are the oven cleaner will destry it.

Typically an oven beeps when the interior temperature macthes the temperature where you set the dial. This is an audible signal to that fact and particularly helpful when you need to pre-heat the oven. For example it you want to cook something at 350 degrees, you set the dial at 350. When your oven reaches that temperature it beeps to let you know. Some cooking directions tell you to preheat your oven. In that case, when you set the dial to 350 and wait for the beep...you know you are safe to start your cooking process because the oven is now pre-heated to the temperature you set. If your recipe requires a pre-heated oven, and you don't wait for the beep, your taking a guess at what temperature you're cooking your food. Additionally, if you want to know what the internal temperature of oven is and your oven is heated...you simply turn you dial setting and listen for the beep. Again, if you set your oven at 350 and you want to know how hot your oven is... slowly turn the dial setting. If the oven beeps at 275 then that's how hot your oven has gotten. To let it finish heating to 350 just reset the dial and wait for the beep.

The Taylor oven thermometer you bought is decent at best. It is most likely the sensor inside the oven. Has your clock displayed any fault codes? F, followed by a number? Changing the sensor will probably correct the problem.

hummmm this sounds similar to what is happening to me. I am praying someone will have a solution, I don't want to have to explain to my daughter who is going to be 4 tomorrow, why I can't bake her cake.

I have just checked the baking guide in the manual and have found that it may not be us after all. (Maybe this is why they telll us to read the whole manual. Well, I never have) According to the cooking time for Baking, the range is very extensive. For example, an angel cake at 350 could take from 28-50 minutes, buscuits at 375-400 could take 8-16 minutes, layer cakes at 350-375 could take 25-40 minutes, pound cakes at 325-350 could take 45-70 minutes and fresh pies at 400-450 could take 35-60 minutes. Basically, the baking directions on the box means absolutely nothing to use Amana oven owners. We have no choice but to cook our food or baked goods until they are cooked, whenever that may be. :) Linda