FIXED LG LSB5682SW oven heating problem

Zdenka

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Model Number
LSB5682SW
Brand
LG
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1-5 years
Hi, I'm having issues with heating the oven, it won't reach desired temperature, it stops a bit before (if I set it to 250, it stopped at 225ish, if I set 350, it stopped at 335) and then the temperature will just drop. There's no clicking sound ether.
The oven already has new bake element, temperature sensor and new PCB! Ohm readings are normal. I think the only thing left is the relay, but I'd like to check it first, I'm done with buying parts that are obviously not the culprit. How can I check the relay?
Or if you think it might be something else, please, guide me.
Thanks!
 

rickgburton

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The oven already has new bake element, temperature sensor and new PCB!...... I think the only thing left is the relay,...
That's pretty much the entire bake circuit with the exception of the touch/key pad assembly which is no longer available. What relay are you referring to? What are you using to measure the temperature in the oven?
 

Jake

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I think he is referring to this one Rick:

Relay Board 6871W1N012B


--->Verify Aluminum foil is not being used.:)

Rick I think you posted this awhile back and I just located it:

Oven Temp Info .... If I set my oven at 350 it should be 350 at all times in the oven...Not the case... Its actually just an average temperature.
When you set the oven to say 350, both the Bake Element at full power (220 volts) & the Broil Element at half power (110 volts, not all ranges use the broil element but most do) or if a gas range the oven burner comes on and starts to heat the oven to the desired temperature. The first cycle, see chart below, it will over shoot the desired temperature. This is normal. Use the info below to actually determine if your oven thermostat is out of calibration.

--->Program the control for bake at a temperature setting of 350 degrees F.
--->Allow the oven to heat for at least 15 minutes or until the high and low temperature readings stabilize and become consistent.
Overshooting of the oven temperature occurs on the first cycle of the control because components have not reached operating temperature. Two (2) or three (3) full cycles are required before beginning a check of the oven temperature.
--->Calculate the average oven temperature. Add the high and low temperature reading peaks together and then divide by two (2).
EXAMPLE.
High Peak = 375
Low Peak = 325'
375 plus 325 = 700
700 divided by 2 = 350
Average oven temperature = 350'
Several readings should be taken to provide an accurate indication.

Jake
 

Jake

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The only way to get an accurate measurement of the oven temperature is with a meter and thermocouple.

If you don't have one it is a good investment for twenty bucks. It will pay for itself after the first repair and will come in handy for many other repairs:

Digital Multimeter DM10T


Jake
 

rickgburton

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OK, if the elements are turning on the relay board is good. Some of those grocery store thermometers have an accuracy of ±20°F.
 

Zdenka

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I have digital meter, it's how I've checked Ohms on other elements.
wrong temperature readings aren't the only problem, the oven never reaches set temperature and just shuts off, temperature falls down.
So, if I programmed 350, the oven would heat till 335 and then just stop, shut down, temperature would fall (and I know that because whenever I try to program it again, temperature is always lower then the last reading, in this example 335)

And it's a she ;)
 
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Jake

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What are you using to measure the oven temperature?

Jake
 

Zdenka

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Nothing, but does it really matter since it shuts off and cools anyways? I understand what you're saying, guys, that ovens own reading aren't necessary correct, but I have a problem with not keeping the heat at all after the certain point (and that point is always below the temperature I set)
 

Zdenka

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Here's an example:
I programmed the oven to 350.
It was heating up nicely, then reached 335 and stopped. It was like that for 40ish minutes. After 40 minutes I turned it off (without opening the door!), programmed again to 380 and the temperature reading (on oven display) was 280!
I've opened the door then, and it really was just warmish.
 

rickgburton

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OK, That wasn't the take I got from your first post. I assumed the oven wasn't getting hot enough. So, after the oven cycles off it doesn't cycle back on, correct? In that case it could be the relay board. On the relay board, measure the voltage between L1 and both sides of the bake relay after it cycles off. I don't have the wiring diagram for that model. Can you post a copy of your tech sheet and wiring diagram?
 

rickgburton

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I'm not sure what readings I should have.
rickgburton said:
... measure the voltage between L1 and both sides of the bake relay

The bake element needs 220 VAC (L1-L2). The DLB (Double Line Break) relay is L2 common for both bake and broil elements. L1 is supplied to one side the bake relay and the broil relay. If the broil element works correctly, the DLB relay is good.
RELAY BOARD.jpg

Relay Board 6871W1N012B


What do you want your user name changed to?
 
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Jake

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What do you want your user name changed to?
Thanks Rick, I changed it for her to what she wanted, I messaged her last night.:)

Jake
 

Zdenka

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Thanks guys!! I'll check the relay later, I have to move it and plug it cause it's not in a use for obvious reasons :)
I'll let you know
 

Zdenka

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Hey guys!
Sorry for not hearing from me for a while, but I waited for the new relay until today!
Just to let everyone know, relay was the problem!!
Everything works just perfectly now!
Thanks for your help, and hopefully, if someone else stumbles upon with the temperature all over the place, people, after checking your termistor, check the relay for sure!!
 

Jake

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Excellent Zdenka, glad to hear the new relay board fixed it.:)

Thanks for the update! Rick will be glad to hear that too!

Jake
 
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