I made sure the boiler was full of water . . .
One thing the dealer may ask you after you tell him that is how you made sure the boiler was at the proper level. So now, I'll ask that question.
Proper water level in that boiler is anywhere from 2/3 to 3/4 full. I'm THINKING that that boiler (along with Anita and Vetrano) is about 6.75" tall and so proper water level would be 2/3 to 3/4 of that. A way (emphasis on "A") to check the level would be to remove the tubing and fittings from one of the wands that would allow you to stick a small wooden dowel into the boiler through whichever hole DOES NOT produce interference with the heating element, i.e. a wooden dipstick.