🔍 Key Concepts

• Function of vents on boilers and feed water heaters • What air binding means in a liquid-filled system • Difference between gases, pressure, chemicals, and solids in boiler components

💭 Think About

• Ask yourself: What problem occurs if air or non-condensable gases are trapped in the top of a feed water heater head? • Which of the choices describes something that a small vent on top of a heater is best suited to handle, as opposed to a relief valve or drain? • Think about which items (pressure, sediment, chemicals, air) are normally removed by vents, relief valves, or blowdown/drains respectively.

✅ Before You Answer

• Check which device is normally used to safely release excess pressure (compare a vent vs. a safety/relief valve). • Consider how sediment is usually removed in boiler systems — from the top or from the bottom? • Verify which problem, if not corrected, can stop or greatly reduce circulation/flow of water through the heater.