By the time I was done, I had damaged at least two parts. One, a hard to find, pressure-regulating diaphragm and the other a needle valve. My friend Chuck took the pressure diaphragm to his shop and crimped it back on. Kathy at Wholelattelove.com tech support explained that I needed to descale the needle valve, reassemple, test, and retest until I have the pressure adjusted properly.
Turns out all I had to do in the very beginning was push a little red button to reset the boiler.
In the interim, approximately 12 months, Starbucks has been reaping the benefits of me not having a functional machine at home. Boy, are they going to miss me.
As of yesterday, I have the machine running perfectly again - churning out tasty machiattos, lattes, Americanos, etc. All's well that ends well.