🔍 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).