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Tom Johnston
Tom Johnston, Home Appliance Technician
Category: Appliance
Satisfied Customers: 8007
Experience:  20 years experience
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My oven heats to 350 perfectly as measured by oven thermometer.

Resolved Question:

My oven heats to 350 perfectly as measured by oven thermometer. After that, it'll only heat to 369 when set to 400, 380 when set to 450, etc. Heats fine to 350, but lower heat when set higher. Have replaced the probe and eoc already.
Submitted: 5 years ago.
Category: Appliance
Expert:  Tom Johnston replied 5 years ago.
What is the make and model# XXXXX
Customer: replied 5 years ago.
Frigidaire FEFL79DCA
Expert:  Tom Johnston replied 5 years ago.
Do you have the manual for your unit?
Customer: replied 5 years ago.

I have the service data sheet that was on the rear of the unit, as well as the wiring schematic and the entire parts list.

Expert:  Tom Johnston replied 5 years ago.
Some of the computers need to be calibrated i'am trying to find out if yours is one of them.I'am having a hard time finding a manual for your unit.
Customer: replied 5 years ago.
The unit has worked fine for 3 1/2 years and has just been doing this for a few weeks now. When I replaced the electronic control unit, it is doing the same thing. I could see the need to calibrate if it was heating to a few degrees off the desired temp. But it is about a good 30 degrees off when bumped to higher temps and only gets to 369 when set to 450.
Expert:  Tom Johnston replied 5 years ago.
When did you replace the oven temp sensor?
Customer: replied 5 years ago.
Couple weeks ago. It was part number 37 on the Body section of the Parts List. Replaced part 20 on the backguard diagram (EOC) three days ago. The electronic control has been problematic in other Frigidaire models according to info on the Internet.
Expert:  Tom Johnston replied 5 years ago.

OVEN CALIBRATION

Set the electronic oven control for normal baking at 350°F. Obtain an average oven

temperature after a minimum of 5 cycles. Press STOP/CLEAR to end bake mode.

TEMPERATURE ADJUSTMENT

1. Set EOC to bake at 550°F.

2. Within 5 seconds of setting 550°F, press and hold the bake pad for approximately

15 seconds until a single beep is heard (longer may cause F11 shorted keypad

alarm).

3. Calibration offset should appear in the display.

4. Use the slew keys to adjust the oven temperature up or down 35°F in 5°F

increments.

5. Once the desired (-35° to 35°) offset has been applied, press STOP/CLEAR.

Note: Changing calibration affects normal Bake mode. The adjustments made will not

change the Self-Cleaning cycle temperature.

Customer: replied 5 years ago.
I understand this line of thinking, but why all of a sudden would this be happening after 3 1/2 years of normal operation?
Expert:  Tom Johnston replied 5 years ago.
When you replace the computer it needs to be calibrated.
Customer: replied 5 years ago.
Well, ok then. When I set it to 350, it heats to 348. So setting the offset 2 degrees higher will make it heat 29 degrees hotter at 400 setting?
Expert:  Tom Johnston replied 5 years ago.
Just follow the instructions i sent.
Customer: replied 5 years ago.
I'll do it.
Expert:  Tom Johnston replied 5 years ago.
Ok just remember the manufacturer allows a 10% difference in the temp +/-
Customer: replied 5 years ago.
Just programmed a 5 degree offset. I have it set to 400 degrees. Will let you know if it gets there. Normally it sits at about 369 when set to 400.
Expert:  Tom Johnston replied 5 years ago.
ok
Customer: replied 5 years ago.

Set to 400. Oven beeped like it was at 400, but internal temp says 370.

 

Expert:  Tom Johnston replied 5 years ago.
Thats less than 10% you just need to find a happy medium.
Customer: replied 5 years ago.

Ok, at 450, I get an internal temp of 383, which is greater than 10%. So, when I set the offset does it change the oven temp? Or does it just change the way the temp reads?

 

Expert:  Tom Johnston replied 5 years ago.
It changes the temp how many times are you letting it cycle before you take the reading
Customer: replied 5 years ago.
minimum of 2 cycles, but I still have it set at 450 and the temp is at 383. It has been at least 5-7 cycles at this point.
Expert:  Tom Johnston replied 5 years ago.
Well maybe you got a faulty board.
Customer: replied 5 years ago.
hmmm. that would mean the original board was bad too then.
Expert:  Tom Johnston replied 5 years ago.
Why did you change the board because of the temp?
Customer: replied 5 years ago.
couple of reasons....first the temp issue. seems that up to 350, all is good. incrementally going upward in temp, there is an increase in difference between the desired temp and actual temp. second is that I hear a lot more clicking when setting the temp at 500 and it sits at 385. it's like it knows it isn't at 500, but something is limiting the heating at the higher temps. i don't see any other temp sensors or anything in the parts list, so I went with the electronics.
Expert:  Tom Johnston replied 5 years ago.
All there is is the tempsensor and the board.
Customer: replied 5 years ago.
It would be nice if I had a code or something ya know? Could it be the element?
Expert:  Tom Johnston replied 5 years ago.
Do both elements come on for preheat?
Customer: replied 5 years ago.

I'll check. Should they?

 

Expert:  Tom Johnston replied 5 years ago.
Yes
Customer: replied 5 years ago.
I turned it off and opened the door to cool it down. Then I'll set it to 400 again and check.
Customer: replied 5 years ago.
Well I assume that the top should glow orange just like the bake element when preheating?
Customer: replied 5 years ago.
Okay Tom, the top element works, but only on broil. It does not glow on preheat or on the clean cycles.
Expert:  Tom Johnston replied 5 years ago.
Thats the problem you need to check all the wireing for the broil element.
Customer: replied 5 years ago.
Ok Tom, all the wiring looks good. I turned on and measured 240 across the bake element leads and nothing across the broil leads. Even on clean, the same. But on broil, the top element comes on. That tells me that the wiring to both the top and bottom elements is good because when voltage is applied to both, they work. Now the two elements are tied together by an orange wire coming off the "L2 Out" from the electronic control. Seems that voltage to both isn't being applied when called for (preheat). Common sense would maybe say its the eco I just replaced or the top element. Am I thinking right?
Expert:  Tom Johnston replied 5 years ago.
Does your tester have a ohms setting on it?
Customer: replied 5 years ago.

Yes

 

Expert:  Tom Johnston replied 5 years ago.
Do you know how to check for continuity?
Customer: replied 5 years ago.
not really
Expert:  Tom Johnston replied 5 years ago.
On the ohms setting is there the number 20k?
Customer: replied 5 years ago.
yep
Expert:  Tom Johnston replied 5 years ago.
Set it to that touch the leads together what happens?
Customer: replied 5 years ago.
I get zero
Expert:  Tom Johnston replied 5 years ago.
The wire that goes from the broil element to the board.Disconnect one end and test it what do you read?
Customer: replied 5 years ago.
unplugged the blue wire that comes off the board to the broil element and got zero. there's another wire that comes off the board to both the broil element and the bake element. It is orange.
Expert:  Tom Johnston replied 5 years ago.
Is it a single wire if it is we know it is fine?
Customer: replied 5 years ago.
the blue one i tested was single right from the board to one side of the element. Result was zero. The side of the broil is orange that is spliced together withone side of the bake.
Expert:  Tom Johnston replied 5 years ago.
Ok set the meter to 120 volts take the blue wire put one lead in it when it is removed from the element.Touch the other lead to the metal on the stove turn it on do you get voltage.
Customer: replied 5 years ago.
not to sound stupid, but you want the oven on now?
Expert:  Tom Johnston replied 5 years ago.
Yes to test the blue wire for power.It needs to be disconnected from the element to test it.
Customer: replied 5 years ago.
Okay, I turned the oven to pre-heat with the blue wire disc'd from the element. It does not get any juice at the end I disc'd from the element or at the control unit.
Expert:  Tom Johnston replied 5 years ago.
You have a bad control board.
Customer: replied 5 years ago.
Something else. When I reconnect the blue wire and turn the oven on now, I get 120V at all 4 points on the elements, but still the temp is low at 400 degrees. Is the blue wire some sort of communicator with the control unit? Cause it is getting juice now and not glowing....
Expert:  Tom Johnston replied 5 years ago.
Each wire has to get 120 volts the blue one is not.
Customer: replied 5 years ago.
And the element would not have anything to do with it? Just asking so I can go back to the folks that I ordered the new control unit from and have them send another on out.
Expert:  Tom Johnston replied 5 years ago.
The element works we know that when you put in broil it glows.The control board is bad.
Customer: replied 5 years ago.
and finally, when everything is connected together again and I turn the oven on, i get 120 volts on the blue wire at the element and at the board. I presume that the 120V is coming from the orange wire on the other side cause when I measure at the element where the blue wire connects, i read 120V. Is this normal?
Expert:  Tom Johnston replied 5 years ago.
The voltage is comming from the other wire.
Customer: replied 5 years ago.
Okay, I'll accept that then. Thanks for your time and prompt replies.
Expert:  Tom Johnston replied 5 years ago.
You are welcome.
Tom Johnston, Home Appliance Technician
Category: Appliance
Satisfied Customers: 8007
Experience: 20 years experience
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