A sprinkler system protects a combustible concealed space between a floor and a sloped roof above and includes a water supply line connected with a valve having a body and a passageway connecting an inlet and an outlet. A seal member is located and supported in a body along the passageway to block and open the passageway. A water discharge device is connected by piping with the outlet and installed in the concealed space at a location remote from the valve to spray water onto the Boon A thermal activation component includes a thermally responsive element installed at a location in the concealed space remote from the valve and the water discharge device. A flexible connector mechanically connects the thermal activation component and the valve and initiates movement of the seal member in response to a physical change in the thermally responsive element due to heating thereof.