FIXED Kenmore Gas Oven: Model 790.70502013 will not stay lit

Chris_F

Premium Member
Joined
Apr 7, 2019
Messages
7
Location
ca
Model Number
790.70502013
Brand
Sears Kenmore
Age
1-5 years
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 in another post on this site for this same oven is that 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!
 

rickgburton

Appliance Tech - Moderator
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Messages
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Here's the part you need. The igniter needs to draw 3.6 amps. There's probably a break in the igniter somewhere when it heats up it loses continuity:
5304509706 Ignitor
 

Chris_F

Premium Member
Joined
Apr 7, 2019
Messages
7
Location
ca
Thanks for the reply Rick.

I will go ahead and order the igniter and hope it fixes the issue :)
 

Chris_F

Premium Member
Joined
Apr 7, 2019
Messages
7
Location
ca
Hi Rick,

Somebody has suggested to me that it may be the control board (relay closing too soon) or a sensor issue since it ignites but voltage is being cut prior to reaching the desired temperature. Do you still think it is most probably the ignitor? Do you happen to know of any additional tests I could do to rule out the control board?

Additional info: I seem to have to let the oven/ignitor cool down for 5-10 minutes before I can set the oven to bake and have the ignitor turn on again.

Thanks for the help!
 

rickgburton

Appliance Tech - Moderator
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Messages
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Connect your meter to the igniter and watch the voltage when the igniter turns on and off.
 

Chris_F

Premium Member
Joined
Apr 7, 2019
Messages
7
Location
ca
I connected the meter to the back of the control board where the two wires come out that feed the igniter circuit. When I initiate bake the circuit gets ~120 VAC. This voltage stays constant right up until the relay clicks (~30-120sec after ignition) and the circuit goes to zero volts. The igniter is glowing up until this point.

I am going to order the igniter like you suggested tomorrow.

Thanks for all your help!
 

rickgburton

Appliance Tech - Moderator
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Messages
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No! Don't order the igniter. The control board is the problem. The bake relay shouldn't open until it reaches the set temperature. The ERC doesn't come with the overlay so you'll need to reuse the old one. Use a hair dryer to soften the adhesive and a flat paint scraper to carefully remove it. Clean it before you remove it.
316455430 Clock/timer
 

Chris_F

Premium Member
Joined
Apr 7, 2019
Messages
7
Location
ca
No! Don't order the igniter. The control board is the problem. The bake relay shouldn't open until it reaches the set temperature.
Ok, haven't had a chance to order the igniter yet.

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 wont 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.

Thanks for all the help!
 

rickgburton

Appliance Tech - Moderator
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Messages
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That's correct. Something on the board is causing the relay to lose its supply voltage or the relay itself is bad. Could be scorched contacts.
 

Chris_F

Premium Member
Joined
Apr 7, 2019
Messages
7
Location
ca
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.

Thanks for pointing out the control board, definitely seems like it is malfunctioning.
 
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