AR North America TPP1401/4A Thermal Relief Valve, 1/4-Inch;

The Annovi Reverberi TPP140-1/4A thermal relief valve series are mounted into the low pressure side of the pump manifold and will vent when water temperatures exceed the valve's specifications. The protects the pump from heat abuse. A must for any pump that might ever be left in bypass mode (unloading) for more than 15 seconds! protects the pump from overheating caused by recirculating water.