The fuel oil back pressure regulator on the...

🔍 Key Concepts

• Trace the fuel flow path on the schematic from the booster/boost element through the pump, filters, control system, and back to low-pressure side. • Understand the purpose of a back pressure (bypass) regulator: it maintains a set pressure by diverting excess flow back to a lower-pressure point. • Compare the regulator’s return line on the drawing with the lines connected to the purge valve, day tank/supply, and booster section.

💭 Think About

• Starting at the back pressure (bypass) regulator symbol, follow the small return line: where does it physically reconnect into the system? Upstream or downstream of the booster/boost element? • Ask yourself: to maintain constant pressure at the metering valve, would the regulator send excess fuel all the way back to storage, to a drain, or just back to a lower‑pressure point in the circulating loop? • Look at the purge valve path on the lower part of the diagram: does the regulator’s return join that same line, or does it join a different section of the system?

✅ Before You Answer

• Verify which line from the bypass/back pressure regulator is a return line (arrow direction back toward low pressure). • Confirm whether that line joins the fuel supply/from tank line, the purge valve discharge/drain line, or the line leading into the boost/booster pump inlet. • Make sure you are not confusing the bypass relief valve (protects against overpressure) with the bypass/back pressure regulator (controls operating pressure in the control system).

The fuel oil back pressure regulator on the fuel system shown in the illustration, returns fuel to which of the following? Illustration GT-0021

Purge valve discharge.

Booster pump discharge.

Fuel oil day tank.

Booster pump suction.

🔍 Key Concepts

💭 Think About

✅ Before You Answer