Pumps must be sized for maximum expected flow rates, so much of the time, pumps are idling against a dead head or much lower than design flow. In such cases, the pumps energy is transferred into heating the water in the pump casing. When pumps run under such reduced flow conditions, the water temperature inside the pump casing can easily reach dangerous temperatures. The result can be damaged seals or even more serious pump damage. Another serious concern may be exposure of humans to the elevated water temperature from the pump when operating water spigots, showers, and other such water supplies.