Your "Mazzei " is just a simple single stage venturi tube using Bernoulli's principles . You need .5 psi (absolute pressure) to boil water @~80F. Even the best venturi tubes won't get you there. There are are a lot of venturi calculators on the web if you want to do the math first before you buy a mazzei that won't boil water. Search under:venturi,venturi tube,aspirator,venturi tube simulation,venturi tube flow calculator.

BTW: water is a refrigerant