🔍 Key Concepts

• Trace the fuel flow path from the pumps, through the heaters/filters, toward the boilers and note exactly where valve "H" is located in that line. • Compare the symbol for valve "H" with the symbols used for other valves that clearly control flow rate, recirculate fuel, or act as quick‑closing/emergency valves. • Think about which component in a boiler fuel system normally adjusts how much fuel is burned at the burners versus which components are used for safety shutoff or isolation.

💭 Think About

• Does valve "H" have a return line connected to it, or is it simply in series with the main supply line to the boiler headers? How does that affect which functions it can perform? • If fuel cannot pass valve "H", what parts of the system are isolated? Would that stop the boiler from receiving fuel entirely, or only change the amount that gets through? • Where in the system would you usually place a device to regulate burner firing rate—right at the boiler burners, or back on the common fuel supply manifold like "H" is shown here?

✅ Before You Answer

• Verify whether valve "H" has any bypass or branch that would allow recirculation of fuel when it is operated. • Check if there are separate control valves at or near the burners that already handle fuel‑flow regulation to control the firing rate. • Confirm whether valve "H" is labeled or drawn with an emergency/quick‑closing style symbol rather than a throttling or non‑return (check valve) symbol.