N.Y. Comp. Codes R. & Regs. Tit. 12 §§ 4-14.4
Provision shall be made for the expansion and contraction of steam mains connected to boilers by providing substantial anchorage at suitable points, so that there shall be no undue strain transmitted to the boiler.
When feedwater or makeup water is introduced from a pressure line, it shall be connected to the piping system and not directly to the boiler. Feedwater shall not be introduced through the opening or connections used for the relief valve, the water column, or the water gage glass.
All hot water heating systems shall be so installed that there will be no opportunity for the fluid-relief column to freeze or to be accidentally shut off.
If a hot water heating system is equipped with an open expansion tank, an indoor overflow from the upper portion of the expansion tank must be provided in addition to an open vent, the indoor overflow to be carried within the building to a suitable plumbing fixture or to the basement. If the system is of the closed type, an airtight tank or other suitable air cushion must be installed that will be consistent with the volume and capacity of the system. Provision must be made for draining the tank without emptying the system.
Where a stop valve is used in the supply pipe connection of a single boiler, there shall be one used in the return pipe connection unless a proper return loop is provided.
A stop valve shall be used in each supply and return pipe connection of two or more boilers connected to a common system. Provision shall be made for cleaning the interior of the return piping at or close to the boiler. When stop valves over two inches in size are used, they shall be the outside-screw-and-yoke rising-spindle type, or of such type as to indicate at a distance by the position of the spindle or other operating mechanism whether it is closed or open, and the wheel may be carried either on the yoke or attached to the spindle. If the valve is of the plug cock type, it must be fitted with a slow-opening mechanism and an indicating device, and the plug must be held in place by a guard or gland. When stop valves are used, they shall be properly designated substantially as indicated by the following tags of metal or other durable material fastened to them:
| Supply Valve-Number () | Return Valve-Number () |
| Do Not Close Without Also | Do Not Close Without Also |
| Closing Return Valve- | Closing Supply Valve- |
| Number () | Number () |
The area of the openings shall be at least equal to the aggregate area based on the nominal diameters of all the safety valves with which it connects. A screwed connection may be used for attaching a safety valve.
N.Y. Comp. Codes R. & Regs. Tit. 12 §§ 4-14.4