The many types of existing gas valves can easily give you, the homeowner, a quick headache, but there is an answer: the universal gas valve. No more confusing choices, because a Honeywell, universal gas valve is compatible with each and every system. You may want to take a look at the universal Honeywell VR8304 Gas Valve right away.
Gas valves are devices that regulate gases such as natural gas and liquid propane. Used for several applications gas valves are available in a variety of sizes flows, inlet and outlet ports, and pressure ratings. One is made of plastic such as polyvinyl, polytetrafluoroethylene, chlorinated polyvinyl chloride, or a metallic substance such as brass, bronze, steel, iron, copper, or aluminum, to name a few. If you are not interested in a universal gas valve, be sure to have your type and model number ready to start narrowing down your options and making your final decision.
Solenoid, electrically actuated ball, proportioning, elliptic, pinch, check, diaphragm, elliptic, metering, needle, plug, pressure relief, and stopcock are all types of valves with specialized characteristics to choose from. Valves come with different sealant materials as well. Some of these are NBR (Buna-N), EPDM (Ethylene Propylene), FKM (Viton), and PTFE (Teflon). NBR is the most common sealant and used for temperatures from 0 to 180 degrees Fahrenheit. EPDM is for hot and some fluid applications, in the temperature range of -10 to 300 degrees Fahrenheit. FKM is specifically for hydrocarbons such as gasoline and its temperature range is from -10 to 300 degrees Fahrenheit. PTFE is used for many temperature ranges as it is the most chemical resistant sealing material. Certain valves are specifically designed for an individual product or product line, so if a name is unrecognizable from what you have discovered from this information, this could be the type of valve you have come across.
First of all, you need to differentiate between your system type, liquid or gas, and match the necessary valve material. When pressurized gases are involved, it is necessary to use a metal valve. Teflon is appropriate for stronger, more corrosive chemicals. Next, decide between the pressure and flow rate your system will require. (Metal can handle higher pressure.) Also keep in mind that solenoid valves are best for continuous on / off cycling and ball valves are easiest to maintain. Finally, decide on a normally closed or normally open gas valve depending on how often you expect your valve to be in use. Some factors to also consider when choosing your gas valve are pipe size, orifice size, pressure and vacuum range.
Terms to remember are the PSIG-maximum pressure and INHG-maximum vacuum. Maximum pressure indicates the amount of substance that can safely flow through the valve, but can also be affected by temperature or chemical makeup of the gas substance. Maximum vacuum indicates the top vacuum pressure that the valve is capable of operating, also affected by temperature or chemical makeup at times.
Proper sizing is key when replacing your gas valve, so be aware of NPT (National Pipe Thread ports) and orifice sizes as these are important in indicating how much fluid is able to flow through the valve. Again, for one of the easiest ways to go, we suggest trying a universal gas valve, where you can forget the chances of making a mistake in sizing or maximum pressure.