I celebrated too early. A couple of days ago, on it's third run the portable space heater had a malfunction. There's an igniter hidden under the main red valve knob on the top right of the heater.The piezoelectric stopped making"clicks", and there was no spark, which meant the piezoelectric igniter broke down. This is a mechanical design error. The knob pushes too hard on the piezoelectric device, easily breaking it after a few uses.
Not being able to return it on account of a lack of receipt, and the fact that any heating device has been flying off the shelves, I decided to fix it. And I made an educational find along the way. I'm sure those of you who have experience in gas appliance repair will probably laugh at me a bit, but in my defense, I know a bit about airplanes and rockets and not much about residential gas hardware.
The easiest route was to replace the piezoelectric spark generator, by using a lighter's igniter. Experiments showed that the spark was too weak. And I had another problem: I couldn't understand why there were two "electrodes" next to the pilot nozzle (which looks like a tiny torch. I understood that as long as one lead from the igniter was connected to ground (all of the metal plumbing and chassis) then you only needed one wire connected to a single needle embedded in a ceramic insulator. The spark would jump from that needle to the closest and sharpest metallic object near that electrode.
Having a second "ground" made no sense to me. I ended up going to the hardware store seeking a gas grill igniter. I was willing to try an electronic gas grill igniter, to install somewhere on the housing of the heater, but I ended buying a piezoelectric gas grill igniter, which basically looks like a long electric button switch. Easy to install and replace.
I almost cut the cable going to the"second electrode" when my mind kept telling me something was wrong. You see, the spark from the new igniter had a voltage large enough to jump between the nozzle of the pilot torch and the ceramic electrode (which clearly was connected to the piezoelectric igniter), *even if I didn't connect the ground lead to the igniter* at all! The black plastic to which igniter was mounted already was conductive enough at the voltage of the spark. So it made even less sense that youl'd need a "second electrode at all! It could not be an electrode!
Upon closer inspection, I saw a white wire go from the "second electrode" to a gravity tilt sensor, and then continue up towards the gas valve which has one tube feeding the pilot torch, and one tube feeding the main burner. It made even less sense to me. Was it an electric wire going *into* the mechanical gas valve?? It couldn't possibly be a ground wire. So it finally dawned on me that this single white wire connected to the valve actually feeds a small electric current to the valve. Interrupt that current and the valve shuts off the flow to both the main burner and pilot.
And it must be an electric current cut off, not a ground short circuit, for the action of the tilt gravity device is to interrupt the current in the wire. That "second electrode" is not an electrode at all! It generates a small current from the heat of the pilot flame. If the pilot shuts off due to lack of oxygen, the all the flow of gas into the main burner tile is stopped as well as the pilot nozzle (the manual reads that it has a special "calibrated ruby" device to limit the flow of oxygen such that if the oxygen level is low, the pilot flame is extinguished).
Similarly it's fairly obvious that this thermoelectric needle will respond the same way should the wind blow out the pilot flame. And lastly, the tilt gravity switch interrupts the same signal.
So this may be very common nowadays, and you can laugh at me now, but basically you have a solid state device in the shape of a needle creating a small current from the heat of the pilot flame to shut down a mechanical valve somewhere else. It's a bit wondrous to me. So having figured exactly where the spark needed to hit (the pilot nozzle), I reconnected the wire going to the gas valve, and only cut the single cable that comes from the original piezoelectric igniter toward the ceramic electrode assembly. I connected the wire to the new piezoelectric device and the ground wire was connected to the chassis of the heater. Assembled the whole unit, and it's working again.
To my amazement, the heater shut down when I tilted the heater, and when I blew out the pilot. And I almost bypassed those safety features!
*Images of a monolith flash and "Thus Spake Zarathustra" plays in the background. Simians create weapons out of bones and invent war*
So back on track again. Functionality restored save for the awkward igniter button sticking out from one side - in spite of my ignorance.
PS. Don't call me for your gas plumbing needs.
