Each hot water boiler shall have a pressure or altitude gage connected to it or to its flow connection in such a manner that it cannot be shut off from the boiler except by a cock with tee or lever handle, placed on the pipe near the gage. The handle of the cock shall be parallel to the pipe in which it is located when the cock is open.
The scale on the dial of the pressure or altitude gage shall be graduated approximately to not less than 1-1/2 nor more than three times the pressure at which the safety relief valve is set.
Piping or tubing for pressure- or altitude-gage connections shall be of nonferrous metal when smaller than 1 in. pipe size.
Conn. Agencies Regs. § 29-232-97