I was having a cold brew with a co-worker and we were discussing thermocouples in direct-vent gas fireplaces. He said he has customers with Heat-n-Glo DV without a thermocouple. I think he said it was a SL-750. I don't recall running across any of these beasts and they don't sound like I would want one installed in my home without a quick drop out TC.
Was he mistaken in what he saw and what other DV have no TC, only a TP?