Cold water supply pumps must be sized for maximum demand while maintaining the correct pressure throughout the building even though, most of the time, the pumps are not actively pumping that kind of capacity. When the water demand in the building is less than the maximum demand, the pump is running on an inefficient portion of the pump curve and the excess pump energy goes into heating the water inside the pump. If the temperature inside the pump casing gets too hot the result can be damaged seals or even more serious pump damage. Another concern of the high temperature water inside the pumps is the exposure to humans when operating faucets, showers, and other water supplies.
The ECONO/HAT-RA can provide thermal relief for domestic water supply booster pumps to keep them cool during idling. If the water in the pump starts elevating to temperatures higher than specified, the valve will modulate open discharging the hot water. Once the temperature falls back to acceptable levels the valve will modulate closed again. This discharged water can be collected, reused, or repurposed to reduce waste.
The HAT/RA-HP works the same way as the ECONO/HAT-RA, but is rated for higher pressure systems. It’s maximum operating pressure is 1000 PSIG (69 BAR) which permits it to be used as a thermal relief valve on many fire pumps and high-pressure water pumps.