What must each boiler or modular boiler have in relation to shutoff valves?

Each boiler or modular boiler must have individual shutoff valves in the supply and return piping to ensure safety and operational efficiency. This requirement is crucial because having separate shutoff valves allows for individual control of each unit. It provides the ability to isolate a specific boiler for maintenance or repair without affecting the operation of others in the system. This isolation capability enhances the reliability of the entire heating system and ensures that necessary maintenance can be executed without shutting down the entire system, which can be critical during colder months when heating is essential.

This approach also helps in preventing potential hazards associated with pressurized systems, where shutting off all boilers simultaneously could lead to pressure build-up or other issues. Therefore, having individual shutoff valves is an important safety measure that aligns with mechanical code requirements aimed at minimizing risks in boiler operations.