In which conditions might a thermostat need adjustment?

A thermostat may need adjustment when the temperature reading is inaccurate. This situation indicates that the thermostat is not providing a reliable measure of the actual water temperature, which could result in insufficient heating or overheating of the water. An inaccurate reading can stem from several factors, including miscalibration, sensor issues, or external influences like drafts affecting the thermostat's reading. Therefore, adjusting the thermostat ensures it accurately reflects the desired temperature, maintaining comfort and safety in hot water systems.

In contrast, the other conditions do not necessarily require thermostat adjustments. While a continuous hot water supply could indicate an issue with the thermostat, it does not directly imply that adjustment is needed unless the temperature is also not where it should be. A functioning return loop typically signifies that the hot water system is operating correctly, thereby negating the need for thermostat modifications. Lastly, while installation of a new water heater may sometimes involve checking the thermostat, it does not automatically mean that an adjustment is necessary unless specific performance issues arise post-installation.