Maytag gas over reads wrong temp

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Old 10-07-09, 05:23 AM
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Maytag gas oven reads wrong temp

RE: Maytag CRG9700 Gas range.
I set the oven temp to 400 degrees. When the control beeped, the indicator read 400, but it was definitely not that. I measured with an external thermocouple and the temp was actually 220 degrees. I raised the set point of the controller to 550, and after the indicator read 550, I measured the the temp with the external TC and found it to be in the range of 330-350.
I recalibrated the controller to the +35 degree max and the temp of the oven went up to over 500 (measured by the external TC). I lowered the oven set point to 400 and the TC measured temp dropped to 250.
There is no smell of raw gas now like there was before I replaced the ingnitor a couple of years ago.
I'm not sure whether the problem is the sensor or the control module. Please advise. Thanks
 

Last edited by timoch; 10-07-09 at 05:30 AM. Reason: Mispelled words
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Old 10-07-09, 12:12 PM
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Angry Re: Maytag oven

Update on oven temp. The sensor checks out at 1060 ohms. I noticed when I set the temp at 400 degrees. When the oven temp is indicated it shows 250 degrees even though the actual temp is room temp. This would suggest to me that the reference thermocouple in the controller is off, or the the related circuitry has deteriorated. I don't see any apparent means of calibrating the reference circuit. The calibration procedure will offset the error, but is limited to +/- 35 degrees.
Unless there is something that I am overlooking, it looks like the controller shot, which means that I will need to replace the stove. since the chance of my finding another controller is nil.
 
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Old 10-07-09, 03:47 PM
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Sorry about your oven troubles. I had the opposite, mine would say it was at 350 when in reality it was 600. I also ran into the 35 degree barrier.

You can get new controller, mine listed at almost $200. It was easier to replace the stove instead. Just do a search on appliance parts and have your model number ready.
 
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Old 10-09-09, 07:00 AM
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Hello timoch. Welcome to Gas Appliances topic and our Do-It-Yourself Web Site.

Care to advise what condition and/or problem caused you to begin checking the ovens temperature? Was the oven burning or under baking any food items? Which would prompt you to begin the temp and ohm checking? Calibrating checking, etc.

Based upon the temps indicated by the external meter, the ovens temp should be under baking all food items. If so, advise. Knowing why you began checking often helps determine a possible cause more so then checking temps etc.

Have you inquired as to what the most common and or likely causes are from your local appliance parts retail store person. They are likely to also know and provide the possible solution(s). Often worth a try imo....
 
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Old 10-09-09, 10:11 PM
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The first hint was when I set the temp at 400 degrees to bake a frozen pizza, and when I checked it after 25 minutes it was still raw. I have a multi VOM tester which came with a thermocouple so I used it to measure the actual temp which was about 225. Oddly enough, when I cranked the control up to 550 degrees, the actual temp went up to 550 degrees, but when I lowered setting on the controller at all, the actual temp started drifting down until there was a 175 degree error.
I located a supplier who has a new controller, but at a price of $285 +s&h. I can get a good newer used stove for less, so unless I can find a way to repair the circuit boards in the controller, it's scrap city for the old stove.

Thanks for the help anyway.

Ps... Cooking the pizza at 550 degrees gave me the best pizza that I have ever baked.
 
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Old 10-12-09, 09:47 PM
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Thought you might like to know what I found. I asked my son the engineer and he said it was most likely bad electrolytic capacitors in the circuit board of the temperature controller. Sure enough, when we examined the board, there were two leaking caps... we replaced them at a cost of $1.00, and now it works.
 
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Old 10-13-09, 04:00 PM
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That was a good find. Good work.
 
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Old 10-31-09, 03:46 PM
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Similar problem

Maytag MGR5875QDQ
It initially heats to the correct temperature, and then when restoring heat, it exceeds the temperature by 53F. The easy solution is to set the temperature lower by 47F. However, DW is concerned it will not be reliable.
Would looking for bad caps be advised or should we just wait for total unreliability?
 
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Old 12-26-09, 10:04 PM
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Replacing capacitors

Originally Posted by timoch View Post
Thought you might like to know what I found. I asked my son the engineer and he said it was most likely bad electrolytic capacitors in the circuit board of the temperature controller. Sure enough, when we examined the board, there were two leaking caps... we replaced them at a cost of $1.00, and now it works.
Thanks to timoch, I was able to fix my oven too! I figured it was a long shot I'd have the exact same problem, but when I took apart the clock module, I saw 2 capacitors with green corroded top and legs. Voila, I replaced them and now it's working again! Here are the troubleshooting steps, in case anyone needs them:

MODEL: Maytag CRG9700 Gas range (manufactured 1994)
SYMPTOM: Oven bake temperature is way off. At room temperature, it was reading 375F
DIAGNOSIS:
1. Set the oven bake temp to 500F. Oven turned on OK and heated up, eliminating any issues with ignitor or valve.
2. Switched off the circuit breaker and pulled out the range by 2 feet and removed the back panel by unscrewing 6 screws, 3 on each side. Checked the temperature sensor's resistance by disconnecting the plug on the left (facing the oven) in the back. The reading was 1100 ohm at room temperature, which was OK.
3. At this point, the only culprit was the clock module. TURN OFF THE POWER FIRST, either by unplugging or at the circuit breaker. Removed the module by first unscrewing the 2 small screws just under the top control panel, far left and right. Then lifted the control panel gently and pushed slightly to the rear. It lifted out without using any force. Placed it on top of the stove, watching the many wires attached to it. Took a picture of the wire connections, to help put them back in later. Disconnected all wires. Unscrewed 2 small screws that held the clock module housing to the control panel. Now the clock module was by itself.
4. At this point, I had no idea what to look for. The clock module (Model ERC-4737-MCPX, says the label attached to it) had 3 layers of circuit boards. The 2 large capacitors and other components on top looked fine. I couldn't really see the compoments on the second circuit board, so decided to take the top board off. There were 4 black plastic posts that held the boards together. The top of the posts had been melted down to clamp down the top board. I used a plier to break off the melted down tips and used the same plier to pry out the top board (be gentle here not to break the circuit boards). There were 2 additional white posts whose tip could be squeezed with fingernails to release them. When the top board was lifted, I could see 2 capacitors with greenish top and legs from corrosion. I didn't disconnect the flat cable that connects top and middle circuit boards and left it in place.
5. The capacitors were C9 and C10, next to the round buzzer with a copper top. They were pretty small size, about 0.2", and rated at 4.7 uF (read micro farad) 35V. I went to a local RadioShack to get them for $1.19 each. I wanted Catalog #: 272-1024, but all they had was 272-1012, which was larger in size, but equivalent electronically. I desoldered the old ones and soldered the new ones, making sure of the polarity (the minus side has a white line). Before I did this, I had to remove the second circuit board too, to expose the bottom side for soldering -- all I had to do was to unsnap 4 black plastic snaps on one side of the board. The other side was held together by a bunch of wires, so I pulled apart the middle board just enough for soldering (about an inch).
6. I put the board back together (with a bit of struggle). It seemed like the top board would stay put without having to clamp it down, but I used a long plastic cable tie to hold together the top and middle circuit boards, just in case.
7. I reconnected the wires, looking at the photo taken earlier, and mounted the module to the panel, and put the panel back on.
8. Turned the power back on, and turned on the oven in bake mode. Set the temp to 400F, and as the heat was coming on, the temperature reading started out at 100F (the default starting temperature). Perfect and back in business!

EPILOGUE: These steps should be taken only after eliminating all other possibilities. Removing the top circuit board is a bit of work, and should be attempted only when all else checks out. If the board cracks or breaks, that may be the end of it. I was lucky that the 2 capacitors were visually obvious, like timoch's. Otherwise, who knows what else might have gone wrong in the module? Before trying this, I was going to buy the module, but couldn't find an exact replacement.

Good luck, and once again DISCONNECT POWER when removing the clock module!
 
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Old 12-31-09, 01:00 PM
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Beeper not working

After putting it all back and successfully testing the oven, I realized the beeper was no longer working. It took some troubleshooting to realize one of the beeper's 3 copper legs was cracked from corrosion, with green spots like the capacitors. I think it had been weakened from corrosion (the beeper used to make crackling sound before), and while I was taking the boards apart, the impact must've completely severed it off. I was able to solder the leg back together and it's working fine again, with no more crackling sound. Soldering the leg wasn't trivial, because my soldering iron has a thick tip and was difficult to put it close to the leg, which was underneath a large circular plate of the beeper.
 
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