Abstract: A three-way gas control valve assembly for selectively controlling gas flow from one inlet port into two outlet ports or vice-versa, such as may be required for flow control of hydrogen-containing reformate in fuel cell applications. The valve assembly comprises three subassemblies: a metering subassembly disposable within the high-temperature environment in the fuel cell for mechanically regulating reformate flow; an actuating subassembly disposable outside the fuel cell and connected to the metering subassembly for actuating a pintle shaft and valve head in the metering subassembly; and a coupling tube subassembly extendable through an insulative shroud to mechanically couple and thermally isolate the metering and actuating subassemblies.