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GE Free-Standing Range JBP35DD1WW: After about two years of

Customer Question

GE Free-Standing Range JBP35DD1WW: After about two years of service, preheat function not operating properly. Set it to 350, preheat cycles off at 220-240 degrees. After another 20-25 minutes, oven reaches and remains at 350.
I have replaced the control unit (twice) and the temperature sensor. I have tested the lower and upper heating elements (about 6-10 ohms each; I already knew they worked because I can see the elements grow red, the oven bakes and broils, and it self-cleans). The connections and wires on the rear of the range all look pristine.
Yet, after replacing the sensor and the control unit (twice) with the new units from Sears Parts Direct, the pre-heat cycle still malfunctions in exactly the same way. The preheat function still signals prematurely that the requested heat has been achieved; the oven takes another 20 minutes or more to actually achieve the requested temperature; and then the oven stays at the requested temperature.
Can't be a problem with the heating elements: they tested OK and they can be observed to work. Can't be a problem with the temperature sensor, or else the oven would not reach and maintain the requested temperature.
So what's the problem and what is the solution?
Thanks for your assistance.
Submitted: 2 years ago.
Category: Appliance
Expert:  Kelly replied 2 years ago.
Thanks for counting on us to help with your appliance problem. My name is ***** ***** I look forward to helping you! Are you using a standard dial type oven thermometer to test the temperature and compare it to the set temperature on the control?
Customer: replied 2 years ago.
Kelly, I know the oven's own temperature sensing is pretty accurate; otherwise, when the oven finally gets up to the set temperature (as judged by a "standard dial type oven thermometer"), long after the pre-heat cycle prematurely went off, the pizza or cookies or rolls we bake turn out just fine after the specified baking time. So the problem really is that the preheat cycle turns off prematurely. The oven eventually gets to the specified temperature and stays at that temperature.
Customer: replied 2 years ago.
The heating elements function (I can see them glow; the oven bakes and broils; I've tested them for continuity and resistance); the preheat cycle, before it prematurely turns off, functions (it cycles on the top and bottom heating elements); the oven control unit has been replaced twice; the temperature sensor has been replaced. The wires and connections on the back of the range (which is now perhaps two years old) all look bright and new, not corroded or heat-damaged.So: why does the pre-heat cycle turn off prematurely? That's the question.
Expert:  Kelly replied 2 years ago.
The reason I asked how you are determining it is shutting off prematurely is because the sensor in the oven is an electronic sensor. It changes resistance with temperature, reacting immediately. During the preheat cycle, both the top and bottom elements will get hot to get the oven to temperature quickly. The heat from the broil element will, of course, increase the temperature at the sensor very quickly because it is mounted directly next to it. So, during the preheat cycle, it is going to cycle off much faster and the temperature will not be totally accurate. However, if you use a digital thermometer probe to test the temperature during the preheat cycle, you will find that the manufacturers typically allow the first cycle to get to 75-100* F higher than the set temperature (as read by the sensor, which is not 100% accurate because of the close proximity of the broil element to the sensor). A standard oven thermometer is made of wound steel that expands as it heats. They are very accurate but are slow reacting. So, using them to determine the accuracy of a preheat is not an acceptable way of measuring. There is a 30 minute period of what the the manufacturers label "cavity conditioning" that is used by service technicians to measure and adjust the temperature. Meaning, the oven must be on for 30 minutes to achieve a stable temperature before any measurements are taken or adjustments made. For most foods (roasts, chickens, casseroles, etc), a standard preheat is fine and you will see no difference in cooking results. However, if you are making cookies, some cakes, things that require a very short cooking time or are very temperature sensitive, you will need to allow a longer preheat for best results. So, to accurately measure the oven temperature, you will need to allow a 30 minute preheat. Let me know if you have any other questions or need further clarification.
Customer: replied 2 years ago.
Thanks but this is no help. The preheat cycle signals it has reached the set temperature long before it has reached it. Then , with out the preheat function (top and bottom elements no longer both cycling on) the oven takes another 20-30 minutes to actually get to the set temp. This is not how it worked for the first 1.5 years. If you are stumped, just say so and I can save time, tho I've wasted money at this site.
Expert:  Kelly replied 2 years ago.
Wow, interesting reply. I am dumbfounded by your aggressive and insulting manner. Perhaps another will be inclined to assist you at this point. I will place your question back to the list for others to see.
Customer: replied 2 years ago.
Kelly, you can see my frustration. I think I laid out the problem pretty clearly, including what does and does not work, and what steps I have taken to address what other technicians have suggested might be the problem. You gave me a long answer, but it didn't, as far as I can see, respond to the information I provided you. So that is frustrating. I've read your answer three times and, I have to say, it is not responsive to the problem. I'm hoping you or someone else will walk through what I've said with--I have to say it--more attention. I may be missing something in your statement, but at the end of it, it doesn't explain why the preheat cycle prematurely ends (although it did not do that for the first 1.5 years we had the range)--but then the oven heats up to the proper temperature, eventually, and stabilizes. Why does the preheat cycle stop at 240 degrees when I've asked the oven to heat to 350? That's not what it did before, and, although the heating elements, top and bottom, function, I've replaced the control unit twice, and I've replaced the temperature sensor, the preheat cycle still ends at around 240 degrees, although I've set the oven control to 350 degrees. I don't think you've helped me understand what is going wrong and how it can be repaired. That's my frustration.
Expert:  Appliance Guru replied 2 years ago.
Thanks for your question.
I am a different tech.
The preheat cycle is just a timed cycle, it has nothing to do with the actual set temp it is just a set time to allow the unit to start up to get hot. If you do not think so time it with a stop watch when starting it, it will end the preheat the exact same time every single time you start the unit no matter if the unit has actually reached the temp or not. You should be able to see the rising temperature on the control board as that is what temp the board is seeing. Normal preheat time to reach the set temperature is about 15-20 minutes to reach 350 and most preheat cycles are about 12 minutes before the cut out.
Customer: replied 2 years ago.
Thanks. On this range, the control display only shows the temperature you set, not the temperature the oven has reached, so we have had to resort to a dial-type thermometer. But that aside. How do you answer this: for the first 1.5 years we had the range, if we set the oven to, say, 400 degrees, when the preheat cycle beeped to indicate it was finished, the oven indeed was at 400 degrees--measured by the thermometer and indicated by being able to cook a pizza. But after that, when we set the same temperature and the preheat cycle indicates it is finished, the temperature is more like 250--measured by the thermometer and indicated by the inability to actually cook that pizza. After that started happening, I replaced the oven control board: if a timing mechanism was at fault, then the new board should have cured that problem, right? But still the same premature stopping of the preheat cycle. I replaced the board again: still the same problem.So why is the timing now off, and how can it be fixed, it this is just a timing problem?My son says: but maybe the problem is that one of the heating elements is not functioning properly, so the oven does not heat up enough during the set time. That would make sense, if the preheat cycle is just a matter of a certain amount of time. But I've inspected both elements--no problem. I've tested both: low resistance. We can bake and broil: so both are working. Both are working during preheat: I can see the red glow.Is it possible for a heating element to be only partially working (e.g., putting out just half of the heat it should), so that, say, the broil element will broil--although it takes longer: not enough longer to notice in broiling garlic bread--but the heat output is lower and thus during the timed cycle the oven does not preheat to the same high temperature as it once did?If so, then the solution is to replace one or both elements--my guess is: start with the top element.Thanks for actually reading and thinking about the experience and data I reported.By the way, I am shocked that a $100+ control board for a simple range, which actually has a temperature sensor plugged into it, cannot actually display the oven temperature during the pre-heat cycle, AND: that the preheat cycle would be on a simple timer and not at all connected with the measured achieved temperature in the oven!! What does that $100 worth of electronics and connections pay for?Thanks.
Expert:  Appliance Guru replied 2 years ago.
The issue is before you knew it was a timed based preheat you just set it to preheat and it beeped at the preheat temp. Then you assumed it was at temp as the baking was fine for the first 1.5 years. Now the baking is bad so you started to check the temps and are finding a temp issue. You may have a problem with a element, but if the both glow red within a minute or two they are fine. Then it really comes down to the voltage to the unit. Make sure you have 240 volts to the outside two connections at the unit. A low voltage issue can cause long preheat times, that would be about it since proper voltage with the elements should have the unit preheat to 350 in about 15-20 minutes tops/
Customer: replied 2 years ago.
Thank you. ***** ask a few further questions, based on your response?
(1) Three people use the range and we all had the same reaction: all of a sudden, the only thing that changed was that, when the preheat cycle went off, the oven no longer was anywhere near hot enough to bake whatever we put into the oven. Before that change, we could put a pizza into the oven and take it out, cooked, after the amount of time on the box; after the change, we had to wait 20 or more minutes AFTER the preheat cycle went off before the oven was hot enough to cook the pizza. Same with cassaroles, cookies. In the meantime, the range top elements appear to be heating just as they did before and the broiler broils just as it did before.
(2) If the problem is a sudden decrease in the voltage going to the range, when why do the broiler and range top elements still work as they did before? Shouldn't they be only putting out a percentage of the heat they did before?
(3) How, anyway, could the voltage to the range suddenly drop?
(4) Or perhaps you mean the voltage just to the broiler element dropped. I wonder--the broiler seems to broil just as well as it did before the preheat cycle no longer gave us a hot enough oven. But let's say it did: how would I fix that problem--remember, I have replaced the range control unit twice since the problem started: hard to imagine the original unit developed a flaw in the voltage control for the broiler element--and then the two new units came with that same flaw to start with! And yet I don't see any other control unit (resister, box) between the broiler terminals, the wires that connect to them, and where the wires connect to the control unit. So if there is a flaw, it must be in the control unit--but in two brand new units?What am I missing? Really, the range does not seem like that complicated a piece of equipment. And yet there is this definite change in the operation of the preheat function of the range, which means we cannot, for example, cook a pizza until, first, we set the oven temperature to 400 and start the preheat cycle, then, after 15 or 20 minutes, when the preheat cycle goes off, start monitoring the mechanical oven thermometer for another 30 or 40 minutes until the oven temperature has actually gotten to 400 degrees--and then put in the pizza and cook it.Can you respond to my comments above, questioning that the problem could be a reduction of the voltage? Do you have any other suggestions?Thanks so much.
Expert:  Appliance Guru replied 2 years ago.
Does the bake element actually glow red when preheating?
Customer: replied 2 years ago.
Thanks for persisting. I just confirmed it. Set the preheat to 350 degrees and turned it on. In about 1m40s the lower element was glowing bright red. Then it cycled off and the upper element came on, became bright red (though not as bright, to my eye). Then it faded and the bottom element glowed.So both elements are cycling on and off, in turn. Is that normal? One will heat up and glow and then cool down while the other is heating up and glowing and then cooling. To my mind, the oven would heat up faster if the on/glowing part of the cycle was longer for each element, or if they both came on at once.But yes: the bake element actually glows red when preheating.
Expert:  Appliance Guru replied 2 years ago.
That is normal is just cycles the elements on and off for more even temps in the oven. It really sounds like it is working correctly and I am out of ideas as it sounds like everything is operating normally. Lastly check the door gasket to make sure you are not losing heat and that would be about all I could think of.
Customer: replied 2 years ago.
Thanks for trying. Not the door gasket: we would notice the extra heat in the kitchen, and the oven is unlikely to be able to maintain its temperature.Yes, it makes no sense, if you think about all of the components, how they are interlinked, and what the consequences should be if one or another fails. And yet, after 1.5 years of service, all of a sudden the oven changed behavior: when we set the preheat for some temperature, the preheat cycle stops far before that temperature, and we have to wait for 30-40 minutes for the oven to get to the requested temperature only via the one element, not the two elements alternately heating up.So, now, to bake a pizza, for example, we have to set the preheat to 400, and then, after the preheat has cycled off at about 220-40 degrees, wait another 30-40 minutes for the oven to reach 400 degrees, and then pop in the pizza for its 20-22 minutes of cooking. The pizza gets baked, but it takes 30-40 extra minutes.Not so good!Do you have any recommendations left? Junk the range (I was apprehensive about buying a GE range, and I guess I have had my bad experiences from the past reconfirmed)? Ask a local oven repair/GE repair person to make an expensive visit to the house and hope he/she can discover and repair the problem? Magic?Thanks.
Expert:  Appliance Guru replied 2 years ago.
You may want to try GE factory service to see if they can figure out or tell you why it is doing that. I would only use the GE factory service though.