Saturday, September 26, 2020

Smoke emitting diodes

Who knew there were smoke emitting diodes in the rheostat for the fireplace insert blower?

The fan has two elements to the control system. It has an on/off snap-disk thermostat in series with a speed-control rheostat.

The fan unit is self contained so the on/off element is mounted very low and in the corner of the insert. It is mounted below the insulating material that lines the floor of the firebox.

It takes a long time for the fan to kick "on".

I added an additional snap-disk but that did not prove reliable in the sense that there were still multiple layers of metal and dead-air separating it from the firebox.

So I went old-school. I added a simple 125V/3A rated, on/off toggle switch. While installing the switch, a hot wire touched the blower housing for a fraction of a second which energized the SED in the rheostat.

OK, it was probably not the SED. Most rheostats involve windings of resistance wire and a sliding contact. I probably blew out the resistance wire.

I have not one, but TWO rheostats ordered and jumpered across the defunct speed control. The fan runs in full-on or full-off mode.

Note to self: Next time, unplug the unit before fiddling with the electrical guts of it.


  1. The funny thing is that we've all sat through the lesson about unplugging before fiddling, often with varying levels of, um, excitement. And yet we persist. Glad it didn't turn out to be a FIRE emitting diode and turn into one of those "let's all stand outside and chat with the neighbors while watching the house and listening for sirens" things.

  2. Once power is removed, ANYone can do it.. Wheres the fun in that?
    A little game of "Operation" with actual consequences is good for the focus..

  3. My Dad walked me through a hot change of a light switch.
    It when fine right to the point when he said, "Now we carefully put the tip of the screwdriver there, and we are going to be careful not to cross the live wires."
    I might be able to find that screwdriver with the melted notch.
    We always turned off the power after that.

    1. John in Philly,
      I have pair of needle nose wire cutters with a perfect 12 gauge hole burned into the cutting surface. I may or may not have been present when it happened.
      Opie Odd

  4. Just for the record, I am going to install a 3A fuse in-line with the rheostat. Fuses are easier to find and cheaper than rheostats.

  5. When ever I unintentionally ark welded a live electrical circuit, the joke was to wear a welding helmet next time since the flash got everyone's attention.

  6. I used an old-fashioned dial-type light dimmer with mine. No electronics anywhere in that system. Less to fail, and if I need one, I have several that came with the house but were replaced when we moved to LED lights. Yay spares.

  7. I was remodeling a house one time and had to remove and replace a wall heater so we could get a new door in. These were 'in the wall' heaters, so they had a casing and the innards.

    Everything went fine until I was reinstalling the innards, (under power because I'm a dumbass), when I created an arc between the casing and the innards with the very nice watch I was wearing at the time. Thank goodness I was squatting down when I did that because it knocked me ass over tea kettle and blew my watch off my wrist.

    I should have known better because back in the day, I was a radar tech and the first rule was to always remove any jewelry, rings, watches, ect. before working on equipment.

  8. Re unplugging before doing electric surgery- good plan.
    I thought of that today and unplugged my circular saw before pulling the small tidbits of wood that got caught between the blade and the guard. Probably better to unplug it first, ayep.

  9. What I meant to say above and didn't, I was thinking of your post when this came up with my saw.


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