I did some more digging. Yes, you are very correct the pressure in the tank is high. There is a regulator on the tank itself that brings that down to a low level, like .5 PSI. Then, there is a gas valve just inside the heater itself which regulates the manifold pressure (the final pressure of gas as seen at the nozzle), and is adjustable. This is the valve that was not correctly adjusted. It wasn't letting enough gas in, so it was triggering a safety device which checks for correct gas pressure.

The rep was very knowledgable, and even gave me a replacement remote control for no charge since mine was cracked! I have fired the heater and it works like a charm. Too bad the other 99% of the pool building experience was such a nightmare Hopefully the scars will fade over time.