🔍 Key Concepts

• Look closely at how the two heaters marked E are piped in the system (series vs. parallel) and where their outlets join. • Think about standard practice for fuel oil systems supplying multiple boilers – what is usually done to maintain continuous operation during maintenance? • Consider whether temperature control to each boiler is handled here or farther downstream (e.g., by separate control valves or return recirculation).

💭 Think About

• Trace the fuel flow from the pumps through the heaters to the boiler supply header. Do the lines from each heater stay separate, or do they combine into one common line? • If one heater had to be taken out of service for cleaning or repair, could the system still supply heated fuel oil to both boilers? What does that suggest about the reason for having two units? • Ask yourself whether anything in the diagram allows you to independently adjust fuel temperature to each boiler, or whether both boilers draw from the same conditioned supply.

✅ Before You Answer

• Verify whether the outlets of the heaters "E" tie into a single common fuel header feeding both boilers. • Check the valve arrangement around the heaters: does it look like a duplex (one online, one standby) setup or two units dedicated to different consumers? • Confirm if there is any separate fuel temperature control shown for each boiler, or just one temperature-controlled supply for all.