Conn. Agencies Regs. § 29-232-39
All automatically fired steam or vapor boilers, except boilers having a constant attendant who has no other duties while the boiler is in operation, shall be equipped with automatic low-water fuel cut-offs and so located as to automatically cut off the fuel supply when the surface of the water falls to the lowest safe water line. This point should not be lower than the bottom of the water glass. If a water feeding device is installed it shall be so constructed that the water inlet valve cannot feed water into the boiler through the float chamber and so located as to supply requisite feedwater. Such fuel or feedwater control device may be attached directly to a boiler or to the tapped openings provided for attaching a water glass directly to a boiler, provided such connections from the boiler are nonferrous t's or y's not less than one-half inch pipe size between the boiler and the water glass so that the water glass is attached directly and as close as possible to the boiler; the straightway tapping of the y or t to take the water glass fittings, the side outlet of the y or the t to take the fuel cut-off or water-feeding device. The ends of all nipples shall be reamed to full size diameter. Designs embodying a float and float bowl shall have a vertical straight-away valve drain pipe at the lowest point in the water equalizing pipe connection by which the bowl and the equalizing pipe can be flushed and the device tested.
Conn. Agencies Regs. § 29-232-39