Every boiler or modular boiler shall have a shutoff valve in the supply and return piping. For multiple boiler or multiple modular boiler installations, each boiler or modular boiler shall have individual shutoff valves in the supply and return piping.
Exception: Shutoff valves are not required in a system having a single low-pressure steam boiler.
The minimum capacity of expansion tanks shall be determined from Table M2003.2.
EXPANSION TANK MINIMUM CAPACITYa FOR FORCED HOT-WATER SYSTEMS
For SI: 1 gallon = 3.785 L, 1 pound per square inch gauge = 6.895 kPa, °C = [(°F)-32]/1.8.
- Based on average water temperature of 195°F (91°C), fill pressure of 12 psig and a maximum operating pressure of 30 psig.
- System volume includes volume of water in boiler, convectors and piping, not including the expansion tank.