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microamp testing for flame sensor
I need to test for microamps on a flame sensor for a steamer. Since the flame sensor and the ignitor are the same how would this be done? I know on a furnace I test it in series since the ignitor is separate. But I’m concerned the high voltage of the ignitor will blow my meter on this setup.Any ideas?
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17 Replies
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There has to be a ground somewhere coming back to the ignition module, I’ve never seen one without it.
Sometimes there’s just a metal “flange” on the igniter where it sits and one can connect a wire to it either with a spade or it has a stud welded onto it for a ring connector. There’s gotta be a ground somewhere at the igniter.
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There is no ground at the igniter, the only ground is coming off the control module which is then connected to the cabinit. The igiter/flame sensor sits over the main burner. (not sure if I posted pics correctly)
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Hmm, that’s tricky then.
Is there any connection on the module for flame sensing or monitoring?
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Can you post a picture of the ignition module? Typically there will be test points on the module with a + & – next to them.
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Typically you use the ground wire connection at the module if there is no sense wire..
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Additionally, the ground wire at the module that you’ll want to use might be identified as “burner ground”.
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Perhaps I’m testing it wrong. I put one lead on the igniter/flame sensor and the other on the ground wire from the module. Make sure my meter is set to micro amp (u) I get no reading even tho sensor is engulfed in flame. Unit will cycle multiple times while steamer is running, then it decides not to relight and alarm will sound. Reset and groundhog day all over again.
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To reference the picture ectofix posted, I detached the ignitor from the module and put one lead on the wire and the other on the point I disconnected. Thats how I tested me igniters on my fryer.
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@Nafet,
The method you used is good for testing the module on a Frymaster because that fryer’s module has a separate flame sensing wire/ flame electrode from the spark wire/ignition electrode. That configuration is referred to as “remote” sense.
In the case of his Cleveland steamer, the module is different. There’s no separate flame sensing wire/flame electrode. The spark and flame sensing circuits use the same wire and electrode. THAT configuration is called “local” sense.
The problem with LOCAL sensing setups is that you can’t be connecting your micro-amp meter in series with a circuit delivering THOUSANDS of volts for spark…and then expect it to survive that to give you some minuscule micro-amp reading. THEREFORE, many (but not ALL) module manufacturers either instruct a tech to connect the micro-ammeter in series with burner ground, or provide separate test points on the module to make a flame circuit reading.
Honeywell is not one to provide such test points, but Fenwal is.
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Oh, good to know.
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You might want to make sure you check the ground wire at both ends to be clean and not have any resistance at the connections. It doesn’t take much with flame sensing. Especially the connection on the burner end.
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Turn the machine off and take a lighter to the probe/electrode on the flame sensor take the wire off of the tab connector because your amp meter has to be in series not parallel then I would think you could see the reading accurately…
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The module puts out a signal voltage that’s rectified through the falme, a lighter by itself won’t replicate it.
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What manufacturer is the steamer?
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