N.Y. Comp. Codes R. & Regs. tit. 12, § 14-2.3 – Preparation for hydrostatic test.

(a) The boiler shall be filled with water to the stop valve.
(b) The connections of such boiler when connected with other boilers that are under steam pressure shall be blanked off.
Exception:
Where double stop valves are installed in all connecting pipes with open drains between, such connections need not be blanked off.

The owner or user shall prepare a boiler for hydrostatic pressure test in the following manner: