Electric Water Heater Gas Valves The valve is very important. Called gas safety valve relief valve installed in the intake areas, mainly in the heating process is to ensure timely resolve the pressure too much pressure to ensure safe usage, it is generally the safety valve during heating will drop out. But it does not mean that when heated will drip, if the water pressure in the range will not bear the safety valve dripping. To prevent water back, guaranteed state is full of water in the machine, avoid dry when water supply.