A high-pressure boiler shall have a shutoff valve in ____________.

A high-pressure boiler shall have a shutoff valve in ____________.

• A. The supply line only
• B. The return line only
• C. The supply and return lines only
• D. The fuel line

Answer: (C)

Isolating a high‑pressure boiler for service requires being able to stop flow entering and leaving the boiler. Placing shutoff valves on both the supply line and the return line lets you completely shut off the boiler from the rest of the system and safely drain or depressurize it for maintenance. If only one line had a valve, hot water or steam could still circulate or the boiler might not be fully isolated, making servicing unsafe. A shutoff valve in the fuel line is important for burner safety, but the water‑side isolation requirement focuses on having valves on both the supply and return lines.

Isolating a high‑pressure boiler for service requires being able to stop flow entering and leaving the boiler. Placing shutoff valves on both the supply line and the return line lets you completely shut off the boiler from the rest of the system and safely drain or depressurize it for maintenance. If only one line had a valve, hot water or steam could still circulate or the boiler might not be fully isolated, making servicing unsafe. A shutoff valve in the fuel line is important for burner safety, but the water‑side isolation requirement focuses on having valves on both the supply and return lines.