When cold water enters a gas water heater, what happens when the water heats up?

When cold water enters a gas water heater, the heating mechanism is designed to respond to the temperature of the water in the tank. As cold water enters, the overall temperature of the water in the tank decreases. Consequently, the thermostat detects this drop in temperature and activates the burner to heat the water.

As the water heats up, it reaches a predetermined set point, at which the thermostat will signal the burner to lower or maintain the flame to avoid overheating. Therefore, the system will lower the flame to an appropriate level to keep the water at a consistent and safe temperature, rather than allowing it to continuously heat or turning off entirely. This adjustment ensures efficient operation of the water heater while maintaining safe water temperatures for usage.