Author Topic: oven calibration question  (Read 1762 times)

Offline bagjr387

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oven calibration question
« on: August 07, 2014, 06:28:05 PM »
Just one simple question.... why do the whirlpool/maytag/kitchen aid ovens go out of "calibration".   Today I had a Maytag oven that was operating almost 60 degrees low.  I set it 20 degrees higher and it operated perfect.   What makes them go out of calibration? In this case the lady bakes a lot and said the oven was fine for over a year and then.suddenly her baked goods weren't turning out right.   I was under the impression that oven probes were pretty reliable....is that not so?

Offline keithvibe

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Re: oven calibration question
« Reply #1 on: August 07, 2014, 06:48:21 PM »
did you ohm out the oven sensor first?
Oven temp is an average not exact, but I'm sure you know that already.
A bit of info lacking in the post to fully comment.

Offline bagjr387

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Re: oven calibration question
« Reply #2 on: August 07, 2014, 06:57:44 PM »
The bake element was 48 ohms. And the oven probe 1083 ohms I think...it was where it should have been at room temp....I should have included this info....Sorry!

I am only asking because I have even run into ovens that were much newer, even 1 brand new unit, that needed the same calibration...probe is good, element is good...just operates below the right range of temperature..I have only been own my own with this for about a year...but I am a bit puzzled by this one

Online Maytag Man 6725

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Re: oven calibration question
« Reply #3 on: August 07, 2014, 07:01:57 PM »
99.9% of the time sensors are either good or bad with oven sensors. If your temp is off it is usually the control. As was mentioned before you have to average your highs and lows.

Offline keithvibe

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Re: oven calibration question
« Reply #4 on: August 07, 2014, 07:07:29 PM »
i'm sure you know if you set a pre-heat of say 350.. it will pre-heat on the first cycle to about 375-400 then cycle off... when the temp hits about 310-320 it will cycle back on then when it hits 360'ish it will turn off again. Think of it as a sinwave
If the oven temp sensor checks good you need to take an average of about 5-10 on off cycles. Average those temps to get your "set temp"
Hope that all made sense and didn't confuse you.

Offline bagjr387

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Re: oven calibration question
« Reply #5 on: August 07, 2014, 09:40:07 PM »
Thanks for your help!  I am aware of the theory of operation...its just that today I finally decided to post here...This oven (upper) was set to 350, (it was a maytag cwe5800, about 18 months old) and it only hit about 310 or so...then dropped to 275 or so...then continued to bounce from probably 290-310 if it was even that much...so i "calibrated" it up 20 degrees and it averaged out about 355-360..I think it was a "close enough" scenario at that point...up 10 degrees likely wouldve been too little of an adjustment...

Offline olyteddy

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Re: oven calibration question
« Reply #6 on: August 08, 2014, 02:23:51 PM »
I hose clamp a 2" piece of 3/4" copper pipe to my thermistor to test ovens. Helps average things out.

Offline Maintech

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Re: oven calibration question
« Reply #7 on: August 08, 2014, 07:19:52 PM »
one of the OEMs I think WP says to use a calibrated bare tip   thermocouple and take I think a 2" sheet of aluminum foil fold in half 4 times then fold the 5th time around TC  and place dead center of oven. Then you take the average of three high low readings after the 5th cycle of high low.. about 75% of the customers that are asking for calibration ,that I see, are using cheap oven thermometers and think the temp is off. I had one customer that argued with me until I came back with 4 brand new thermo and lined them up along side my thermocouple. the 4 oven thermometer varied by over 75 degrees but not a consistant variation.

Online Maytag Man 6725

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Re: oven calibration question
« Reply #8 on: August 08, 2014, 07:32:38 PM »
I have not yet seen an accurate home owner oven thermometer   . I tell them theirs cost $5-10. Mine costs $250. Which one should they trust. My thermocouple has a pinch clamp like a giant alligator clip on it. Works well

Online theoldstoveguy

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Re: oven calibration question
« Reply #9 on: August 08, 2014, 07:43:13 PM »
Bake the biscuits. I have them do the Pillsbury buttermilk biscuit test. 350 for 8-10 minutes after preheat for 15 minutes. Then if they cook right oven is OK. I ask customers to try that and 90% of calls are cheap thermometer. I ask if their cheap thermometer is correct "how did it bake correctly"? Used this for 30+ years and works better as they have proof in front of them. Also will a oven tester find "hotspots" in an oven,no.

 

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