New York Codes
Both the New York City (NYC) Plumbing Code 2014 and the Plumbing Code 2015 of New York State, which is based on the International Plumbing Code (IPC) contain specifications for hot water supply systems including hot water recirculating systems. Both are similar but not exactly the same, but read together they provide invaluable guidelines for engineers. In general, the IPC has more data that relates to circulating systems and demand recirculation controls for hot water return systems.
In essence, hot or tempered water may be supplied to fixtures that utilize hot water and both heat-traced piping and recirculating system piping are considered to be sources of both.
When thermostatic mixing valves are used in systems that incorporate hot water recirculating pumps, the hot or tempered water is routed back to the:
- Water heater’s cold water inlet pipe
- Thermostatic mixing valve’s hot water return connection
In general terms, the installation of heated water circulation systems is done in accordance with the International Energy Conservation Code (IECC), following different sections depending on the height of the building.
If demand recirculation systems have more than one pump, it is mandatory that a demand recirculation water system is used. Furthermore, controls are required to start the pump automatically when the fixture or appliance senses the flow of hot or tempered water, and controls must limit the temperature of the water in the cold water pipes to no more than 104 °F (40 °C).
When master thermostatic valves are incorporated in the piping of recirculation systems, the hot or tempered water return line must be routed as described above.
Another important factor is that if cold water is supplied to a storage water heater, and the water passes through either a pressure reducing valve, a check valve or a backflow preventer, it is essential to include a thermal expansion tank in the hot water system. This should be correctly sized and connected to the heater’s supply pipe downstream of any valves.
It is also essential for all faucets, diverters, and fixture fittings to be installed so the flow of hot water is on the left.