A multi-way valve unit which provides low pressure unregulated gas flow and high pressure regulated gas flow in an integrated gas control system. A main and bypass diaphragm valves control gas flow through the gas valve system, the main and bypass valves being opened by pressure differentials on their respective valve diaphragms. A regulator valve and a snap valve modify gas pressure applied to the main and bypass valves diaphragms respectively. A control means actuates the regulator and snap valves based on degree of temperature deficiency sensed in a monitored space. The control means opens the snap valve to provide unregulated gas flow when low gas pressure is required, and opens the regulator valve to provide regulated high flow when high gas pressure is required.