How should a water heater burner be tested for proper operation?

Testing a water heater burner for proper operation can be effectively accomplished by running hot water out of a tap. This method creates demand on the water heater, prompting the burner to activate and heat the water. When hot water is drawn from a tap, it signals the thermostat to turn on the burner, allowing you to observe its functioning in real-time. If the burner ignites and the water heats up as expected, it indicates that the burner is operating correctly.

Other methods like adjusting the temperature dial might not directly assess the burner’s function, as they merely change settings without confirming operation. Draining water from a pressure relief valve is typically a safety procedure rather than a test of the burner itself. Similarly, opening the tank drain valve is more about checking the tank's integrity and flushing out sediment, rather than testing burner performance. Therefore, running hot water from a tap is the most relevant approach for observing burner operation in real time.