🔍 Key Concepts

• Relationship between fuel temperature and viscosity/combustion quality in fuel oil systems • Normal function of a fuel oil heater versus safety/relief devices • Typical consequences of overheating fuel inside a heater or purifier system

💭 Think About

• Which option describes something that would gradually result from too high a fuel temperature inside the heater, rather than an immediate mechanical action? • Look at each device mentioned (relief valve, pump suction, recirculating valve): which ones are normally controlled by pressure or flow, and which by temperature effects on the fuel? • What physical change happens to fuel oil when overheated in contact with hot surfaces for a long time?

✅ Before You Answer

• Verify which components (relief valve, pump, recirculating valve) are typically pressure-controlled, not temperature-controlled. • Consider whether overheating would more likely affect the condition of the fuel or instantly operate a specific valve. • Ask whether loss of pump suction is normally caused by high temperature in the heater or by problems like air leaks, low tank level, or clogged strainers.