🔍 Key Concepts

• Fuel oil burner sprayer plate markings and what each number typically refers to • Relationship between the first two digits and the capacity/size of the burner • How manufacturers code information about orifice/slot/whirling chamber on plates

💭 Think About

• Ask yourself: When a sprayer plate has a 4‑digit code, do the first two digits usually describe the flow capacity or a geometric detail like a slot shape? • Think about which part of the burner most directly controls the fuel flow rating that needs a simple size number for quick identification. • Consider: Would a designer be more likely to use a simple number to show a diameter/size, or a more complex property like an area ratio?

✅ Before You Answer

• Check which element of the burner (orifice, slots, whirling chamber) is most commonly standardized and sold by number size. • Verify what the first two digits versus the last two digits on a plate like '2909' are typically used to represent. • Ensure you distinguish between size (dimension) and ratio (relationship of areas) when choosing your answer.