Oven lighting problems.

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Old 08-15-15, 03:33 PM
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Oven lighting problems.

Whirlpool WFG114SWB

Oven set to 400. Was only at 165 after 30 minutes. Noticed glow bar was lit, however, no flame in oven.

Turned off and back on still only glowing bar but no flame and after a few minutes this time oven started to heat properly and achieve the set temperature.


Is it the ignitor that is failing?

perhaps related, the last few months I noticed a very faint wiff of gas at times when the oven is cycling. Just figured I was getting residual from the lighting process.
 
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Old 08-15-15, 03:44 PM
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I think your on the right track with the ignitor. The ignitor must get up to a certain temperature, hot enough to turn on the gas valve. When old they can glow but not get to that magic temperature. Luckily they are pretty easy to replace.
 
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Old 08-15-15, 05:16 PM
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I figure that's the obvious thing... a 25 dollar repair.

If its still occurs, could this be a gas valve issue or something else?

FWIW, the stovetop burners were working while the oven was not heating. I assume that rules out a gas valve.

Also the fact that the glowbar was getting power albeit not igniting says its not a relay or something else prior to the ignitor.

What is most confusing, is that it "fixed" itself and I was able to cook super. Are these things intermittent like that?
 
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Old 08-15-15, 05:42 PM
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The stove top burners operate very differently than the oven. The oven uses a hot surface ignitor. When you turn on the oven it first turns on the ignitor. As the ignitor heats up it's resistance changes and the control board or gas valve is looking for a certain value that say's "it's up to temperature" before it will turn on the gas. When they get old they can reach a point where they are right on the go/no go line so sometimes it works and sometimes it doesn't. Eventually it will reliably not work.

It's a safety feature. The oven will not turn on the gas unless it knows the ignitor is hot enough to ignite the gas. It's designed to be failsafe so if it's not hot enough, is missing or broken then the gas doesn't turn on. The annoying ones are gas ovens with electric browning elements. The electric element comes on and sorta warms the oven but not enough for baking and you're left wondering how can an oven work half way.
 
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Old 08-15-15, 06:27 PM
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thanks for answering me, I appreciate it.

The other thing is the safety valve. From what I am learning its usually the ignitor and then maybe the safety valve.

You mention how the ignitor could be intermittent... I understand that but how about the safety valve? Are they likely to go intermittent? And I assume a bad safety valve then would also still allow gas to the cooktop.


BTW: this is a 2 year old, 500 dollar stove if that means anything in this throw away world of appliances. Ignitor is 20 bucks. Safety valve is 100. bucks. Control board is 275 bucks.
 
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Old 08-16-15, 07:25 AM
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If your ignitor is glowing then the control board is doing it's job and trying to light the oven burner so I wouldn't worry about it for now. The ignitor is relatively cheap and easy to replace and they commonly (relative term) fail whereas gas valves fail less often and are more difficult and expensive to replace so... start with the cheap and easy part.

The gas valve you mention only controls the oven burner(s). Gas is always supplied to the cook top and is controlled by you manually opening the valve. So, even when the power is out you can use the stove top if you use a lighter to light the burners but your oven cannot be made to work without electricity.
 
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Old 08-16-15, 10:57 AM
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In the oven there are only two parts that control ignition. There is the valve and the igniter. They are wired in series. When power is applied the igniter starts to glow. When it reaches the white hot point it draws enough current to open the safety valve and you have a flame.

The valve rarely goes bad. The igniters are a popular failure item. You posted a partial model number. The complete number will need to be given for repair part.

The part number for that igniter should be W10140611. You can search online using that part number to find many parts dealers or go to your local appliance parts retailer.

Here is one place that sells it as well as has a replacement video.
Whirlpool 98005652 Oven Igniter - Appliance Parts Pros
 
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Old 08-16-15, 12:23 PM
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that's the part.

Tried this morning again no flame. Ignitor glowing. Doesn't look all that bright. Its measure 2.8A.

Does that amperage reading tell me that its defective?
 
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Old 08-16-15, 05:36 PM
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How are you testing 2.8 amps?
 
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Old 08-16-15, 05:54 PM
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clamped one of the wires while the igniter was glowing.

Its my understanding I need like 3.2 or 3.6 for the square igniter to open the gas valve. That measurement is just a hair under.... is it really that sensitive that .5 makes a difference or am I barking up the wrong tree?
 
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Old 08-16-15, 06:01 PM
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Yes....it is that sensitive. That's why the gas valve is called a "safety valve."
It won't allow the gas valve to open unless the igniter is glowing white hot.... not just orange.
 
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Old 08-17-15, 06:14 AM
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And that's how they often tend to fail unless they are physically broken. Over time they slowly allow less and less current through. At first the oven works intermittently and finally it drops to the point that it never opens the gas valve. It will still glow but still won't let enough current through to open the gas valve. I also see it happen during power outages when people are running off (undersized or overloaded) generators.
 
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Old 08-21-15, 11:38 AM
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new ignitor fixed the problem.

For kicks, I tested the resistance old vs new. I think the old ignitor was like 300 some OHM the new ignitor was half that. Perhaps I looked at it wrong.

Do you know what the proper resistance measurements are for this ignitor?
 
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Old 08-21-15, 02:05 PM
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I'm glad that took care of the problem.

As for the resistance I don't know and don't care too much (but it's always fun to check). It's a pretty straight forward thing to diagnose and ignitors are relatively inexpensive and a wear item. I don't remove the old one unless I have the replacement in hand so I can install it while my head is in the oven. It's too much work to get down on my hands and knees so I only do it once.

If your new ignitor had half the resistance that explains why the old one wasn't reliably opening the gas valve. If I get bored tonight I'm going to have to Google and try to learn what process it might go through that changes it's resistance.
 
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Old 08-21-15, 06:31 PM
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I think the old ignitor was like 300 some OHM the new ignitor was half that.
A typical over igniter should be around 3.4 ohms.

A typical gas safety valve should be around 1.5 ohms. You need a decent meter with good probes to get an accurate measurement that low.

!20v applied directly to the safety valve by shorting the igniter will immediately render the valve useless.

Igniters are a mixture of compressed carbon granules and a ceramic substrate for strength. The constant heating and cooling can cause the ceramic to start cracking. Any type of crack causes the carbon to lose resistance.
 
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Old 08-21-15, 06:33 PM
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Thank you. I've been on this site 10+ years and I still learn something every day.
 
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Old 08-22-15, 06:18 AM
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pj- its like 3.2-3.6 amps to ignite gas for the square type igniter under load... the cylinder ones are slightly different.

Those high OHM measurements I measured were disconnected, wire to wire. I guess that's not a proper way to test it anyhow or I was looking at it wrong.

Oh well... end of story.. the stove lives another day to cook my potatoes and that's what matters most!
 
 

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