Ace the HVAC Journeyman Challenge 2026 – Cool Skills, Hot Success!

The appliance designed primarily to supply hot water with automatic controls limiting the temperature to a maximum of 210°F is a water heater. Water heaters are specifically engineered for heating water for various domestic purposes such as bathing, cooking, and cleaning. They incorporate automatic temperature controls to ensure safe operation and prevent scalding, keeping the water below the maximum temperature threshold.

Steam boilers, on the other hand, are used for generating steam rather than hot water and typically operate at higher temperatures and pressures. Expansion tanks serve a different function entirely, as they are used in hydronic heating systems to absorb excess pressure changes in the system. Gas heaters are not specifically designed for hot water supply; they can also refer to heating appliances for air or other functions without the same focus on water heating and temperature control. Thus, the water heater's specific design and function make it the correct choice in this context.