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Author Topic: Kenmore Gas Oven: Model 790.70502013 will not stay lit, bad ignitor?  (Read 578 times)

Offline Chris F

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  • Member Since: Apr 2019
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Hello, my oven is a Kenmore 790.70502013 (single oven burner, single ignitor, single gas control valve)

The oven burner intermittently ignites and it will not stay lit long enough to come anywhere close to usable temperature.

Symptoms: Turn oven on to bake/broil. The glow ignitor will glow, the burner will usually ignite in 60-120 seconds, however, the ignitor will stop glowing shortly after burner turns on (within 5 sec to 2 min), when the ignitor stops glowing, the gas supply turns off, and the burner goes out. The oven does not seem to try to relite after this happens, at least not in any reasonable amount of time. Unplugging the oven for several minutes then trying bake or broil again will result in the same thing happening again.

I have taken it apart and tried all the tests I could find online which include:

             All gas supply valves are fully open. Stovetop burners work perfectly fine, indicating the main gas supply is not the issue.

             Glow Ignitor Tests: The removed, isolated ignitor showed to have continuity. The resistance of the ignitor was measured to be 336 ohms. I do not have an amp meter to measure the amp draw of the ignitor.

             Gas Control Valve Tests: The terminals on the gas control valve have continuity. The resistance between the gas control valve terminals (with ignitor removed) was measured to be 2.5 ohms.

             Voltage Supply: The voltage supplied to the gas control valve and ignitor was measured to be ~118 VAC when in bake/broil mode.

             Temperature Sensor: The disconnected temperature sensor was measured to have 1069 ohms of resistance at room temperature, suggesting that it is functioning properly.

             Relay Noise: When the oven is set to bake/broil you can hear a relay switch. The ignitor is supplied with AC voltage and begins to heat. Then the gas control valve opens, and the burner ignites. Shortly after you can hear the relay switch, the ignitor stops glowing, and the gas turns off.

       I am thinking that it may be a failing ignitor? From what I have found 336 ohm resistance on the ignitor is higher than it usual?

       Can a failing ignitor cause the oven to ignite, run for a short amount of time, then turn off? Do you think it could be the oven control board instead of the ignitor?

       Any advice would be greatly appreciated as I am planning on ordering a new ignitor but it is a $80 part for the OEM version. Thanks!

Offline DaleCaskanette

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  • Member Since: Dec 2013
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  • Country: ca
Re: Kenmore Gas Oven: Model 790.70502013 will not stay lit, bad ignitor?
« Reply #1 on: April 07, 2019, 06:00:56 PM »
If it takes that long to light igniter is definitely bad.   Is 120 vols still going to igniter when it shuts off may be cracked

Offline Chris F

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Re: Kenmore Gas Oven: Model 790.70502013 will not stay lit, bad ignitor?
« Reply #2 on: April 07, 2019, 11:30:47 PM »
Thanks Dale,

I have a multimeter hooked up on the back of the control board on the two wires that feed the bake circuit (yellow and white). When I initiate bake it gives out ~120VAC, the voltage stays constant until I hear the click of the relay and all voltage stops. The igniter is still glowing when the relay clicks.

So yeah it still has 120vac going to the igniter the moment it clicks off.

I will try replacing the igniter like you suggested, thanks!

Offline Atech

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Re: Kenmore Gas Oven: Model 790.70502013 will not stay lit, bad ignitor?
« Reply #3 on: April 08, 2019, 07:25:38 AM »
Sounds like a bad board to me. 120v should be coming out until the temp is final temp is reached. To check the ignitor it's best to do an amp draw while the ignitor is glowing. Above 3 amps is usually good. Anything below that is considered weak, and can lead to problems.

Dave

Offline Chris F

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  • Member Since: Apr 2019
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Re: Kenmore Gas Oven: Model 790.70502013 will not stay lit, bad ignitor?
« Reply #4 on: April 08, 2019, 06:42:55 PM »
Sounds like a bad board to me. 120v should be coming out until the temp is final temp is reached.

Hi Dave,

So since the relay clicks and stops voltage to the circuit before the set temp is reached, then it is control board and not the igniter? A bad igniter won't cause the relay to switch prematurely? If it was an igniter issue then there should be a constant 120 volts when bake is initiated until the set temp is reached?

The relay clicks to stop voltage every time it turns off prematurely. So if it should be giving 120 volts the whole time bake is initiated until it gets to the desired temp, it definitely isn't doing that.

Also, during testing yesterday the oven stayed lit and seemed to make it to the set temperature. It worked 3 times in a row, then stopped working again. This was the only times it has worked out of the the ~30 times I have tested it in the past 4 days. Not sure if this narrows possibilities at all.

Thanks for the help!

Offline Chris F

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Re: Kenmore Gas Oven: Model 790.70502013 will not stay lit, bad ignitor?
« Reply #5 on: April 09, 2019, 12:55:07 AM »
I wanted to see if the igniter had any effect, so I disconnected the igniter/gas valve portion of the circuit. Then tested voltage on the control board at the leads that feed the igniter circuit. I was getting 120vac for random amounts of time (50-300 seconds) before the relay would click and turn the circuit off. I also noticed that if I gave the housing above the control circuit a little thwack that the relay would sometimes click over and close the circuit.

Seems like the control board is malfunctioning due to the intermittent behavior with the igniter removed?

Offline Atech

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Re: Kenmore Gas Oven: Model 790.70502013 will not stay lit, bad ignitor?
« Reply #6 on: April 09, 2019, 07:38:13 AM »
Sounds like a bad board. It's almost never an absolute when your dealing with electronic control boards, but I'd say there's about a 90% chance.

Dave

Offline Chris F

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  • Member Since: Apr 2019
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I just wanted to come back and update this thread in case anyone stumbles across it in the future.

I replaced the control board and the oven works perfectly once again.

Thanks for all of the advice.

I replaced it with an "Electrolux 316455430 Frigidaire Clock/Timer"

Offline rkious1

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    • K-ICE Heating and Cooling and Appliance Repair
Frigidaire is famous for bad oven boards .... not in a good way either.
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