What do you do when an appliance, despite all appearances of normality, simply refuses to do its job? The Samurai and I were forced to answer this very question today.
The culprit: A KitchenAid KGRS505XWH05 double oven all gas range.
The complaint: The customer told us that neither the top nor the bottom ovens would ignite, but the cooktop worked fine.
The customer's description turned out to be about right (for once). The upper oven broil and lower oven bake ignitors would glow for 10-20 seconds, and then the control board would shut them off -- you could hear the relay clicking each time it did this. No gas, no flame, no nothing. In addition, the upper bake ignitor wouldn't glow at all.
We go ahead and pull out the range to test the gas valves and the ignitors. Gas valves test good (electrically, at least). But the upper bake ignitor is reading megaohms of resistance. Way out of spec, so that explains why it wasn't glowing at all. The other two ignitors, however, are reading about 3.3 amps of current during run. That's borderline, but they should still be capable of igniting the burner. And it doesn't explain why the board is shutting them off after they've started glowing.
Just replace the bad ignitor and slap in a new board, right? That'll fix all the problems!
Not so fast. While lesser techs might have gone full PCM, we instead cracked out the tech sheet to see how to speak this board's language.
This model actually has a pretty nice service mode. You can manually activate each load, check for error codes, do a control reset, all kinds of stuff. We found that when we manually activated the functional ignitors, they would glow, and the board wouldn't shut them off by itself. Progress! We just confirmed that the board is, for some reason, making a decision to shut off these ignitors during normal operation. But they're perfectly capable of staying on if you manually activate them.
So what now? Maybe the error codes can give us some more info. We retrieve the error codes and, lo and behold, there is one: F1 E0. That's a MICOM communications error, and you know what the tech sheet says to do about it? "Replace the control."
Okay, so now you replace the board, right? The tech sheet is telling you to!
We weren't satisfied with that answer. Surely, there's more to be found here? We decided to take advantage of the tools provided by the machine's service mode and do a control reset. Then, we cleared that F1 E0 error code and cycled power to the range. The question to be answered here was this: was that error just a one-time deal, or will the control generate it again?
After power was restored, we retrieved the errors again: no codes.
We've proven that the error wasn't a recurring one! One last time, we test those upper broil and lower bake ignitors. They glow. We hold our breath.
And then, those beautiful blue flames.
What happened here? Well, we don't really know what caused that F1 E0 code in the first place. It's possible that a power surge scrambled the control's brains a little. Whatever the case, just the presence of that communications error code prevented the board from wanting to run the ignitors. Why it would be programmed that way escapes me. But then again, the addled minds of Whirlpool's engineers are mysterious, aren't they? The control reset might have helped as well, so I recommend you do that in addition to clearing the error code if you encounter this problem yourself.
The lesson here is this: always be thorough and logical in your troubleshooting. Figure out how the board thinks and how to talk to it -- replacing it should always be a last resort.