Superior vent-free milivolt igniter puzzle: OFF(spark) PILOT(no spark) ON(spark)

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himawari

New Member
Apr 23, 2020
3
Livonia, MI
Hi -- I'm hoping someone can help me puzzle this one out! We have a Superior DRT3035 DMN vented insert that we installed 2 years ago. Recently, the pilot did not want to spark and ignite the gas pilot. I find that the piezoelectric will visibly spark when in the OFF position, and also in the ON position, without any pushing in on the control knob. However, when I turn to PILOT and try to get a spark, I can't get it to spark when pushed in, but it will spark when not pushed in. Would this be a wiring issue?? Thanks for your advice!
 
Your title & your post are confusing. Is it vented or not?

Hi Bob -- sorry, I meant to say that it is vented. It is not an insert.

My post is confusing because I'm confused! I know the piezoelectric igniter is good, since it sparks in the off and on positions, and will spark in the pilot position if I don't press the knob in. I know the thermocouple is good, since I can press the knob in and light the pilot flame with a butane lighter, and after holding in for 10 seconds let go and it stays lit. I can then turn the knob from pilot to on, and and the fireplace will fully light up.

So I can't see what part might be causing any trouble, and the only time I can't get a spark is when I need it (with the knob pushed in at the pilot position to light the pilot flame). Frustrating!!
 
It's very consistent. I'm only checking when the fire's not on, but sparks are consistent in all 3 positionings (off-pilot-on), and it's only when I press in the knob to engage the pilot gas that the sparks fail... I've got the pilot flame lit right now, and it produces consistent sparks.

Does pressing in the pilot knob engage or disengage something in the circuit? Thanks for your responses!
 
Pressing on the Off-Pilot-On knob - while in the Pilot position - allows the gas to flow to the pilot.
It has to remain depressed until the pilot flame generates enough milliVolts to keep the gas flowing.
It has nothing to do with the piezo igniter. I would check to see if the spark is jumping from the piezo
to another location. Don't know how old your unit is, but the sheathing on the wire can deteriorate
over time, which can allow the spark to jump to the nearest ground, instead of the pilot hood. The best way to check for an erratic jump is with the light dimmed or off...
 
I've run into many times when the gas flowing from the pilot when the knob is pressed creates a small oxygen depletion, and without the right amount of air present the spark may not be able to travel. I often try to compensate for these by vigorously attacking the piezo (like snapping it 7-8 times in rapid succession), particularly trying to time the first piezo spark with the initial depressing of the pilot knob.

Beyond that opening a glass front (if a DV) can help, or if the system is standing pilot anyway, just lighting the pilot with a lighter or match and shrugging.