>the price that Cass paid seems excessive.
I just have to ask, excessive compared to what? Boiler engineering and fabrication is not simple cut-and-paste stuff that can be done in someone's garage in exchange for a few cases of beer.
If it's done right, it does cost a tidy sum, and you DO get what you pay for. Having seen it and knowing what went into it, Cass got their money's worth. In some ways, they got a bargain.
The costly ones are those that don't meet any kind of design code and are just slapped together. You not only pay for the unusable mess that results, but you pay again to have a correct, code-compliant boiler built. Now THAT is excessive.