Propane tank valves

All propane tanks are fitted with different valves to regulate propane flows. Propane tank valves are shown in the diagram below. Bear in mind that prices shown are only indicative and that if you have a propane tank installed you should select one that comes fitted with all the necessary valves.Propane valves and regulators

Relief valve

The safety relief valve (also: pop off or pressure venting valve) is crucial to your propane system and your safety because it relieves excess pressure that may accumulate in the propane tank (and cause it to rupture). Older tanks have external relief valves but mostly tanks are fitted with internal relief valves, which make it easier to move the tank if necessary. Relief valves operate through a spring under pressure which opens the valve slightly when tank pressure rises to the same level as that of the spring or opens it fully if tank pressure is higher than spring pressure. It closes automatically. The price of safety relief valve varies between $50 and $100.

Fill valve

The fill (or filler) valve is used to fill your tank with propane. This operation involves a propane delivery truck driving onto your property and screwing its hose onto the filler valve. Risks of propane escaping during delivery are avoided by positioning the hose end against a gasket inside the fill valve. The fill valve opens automatically with pressure from the propane in the delivery hose. To avoid leaks fill valves are configured to allow propane flow in only one direction, which also means that once the tank is full and the hose withdrawn there is no risk of propane escaping. The price of fill valves varies between $30 and $60.

Service valve

The tank service (or shut-off) valve allows propane vapor to enter the gas system and fuel appliances downstream. Since it connects propane to your home it is an important element of ensuring your propane installation is safe. Unlike other valves that may present throughout your gas plumbing system the service valve is placed on your propane tank and controls ALL the gas flow. It can be used to shut the entire propane system down if necessary. It works a little like a water tap in that it is opened and closed by turning a hand wheel but unlike a water tap it does not regulate flow (regulators do that in propane systems). Propane service valves cost around $30.

Vapor eliminator valve

The vapor eliminator valve (or vapor return / vapor equalizing valve) are required on propane tanks to facilitate propane delivery, especially during hot weather. It enables excess pressure to be relieved as the tank is being filled (as opposed to in general, which the safety relief valve does). In doing so, pressure is equalized between the propane truck tank and your residential propane tank. Rather than being released into the atmosphere, excess propane is returned into the propane truck tank. Vapor eliminator valves cost around $30.

Liquid withdrawal valve

The liquid withdrawal valve allows for propane to be drained from your tank. Although liquid withdrawal valves are fitted onto propane tanks they cannot be operated without extra fittings that only propane companies have, for safety reasons (a second valve that needs to be attached for liquid propane to flow). Liquid withdrawal valves are used by propane companies when a tank needs to be emptied before it can be moved: propane tanks in excess of 5% capacity cannot be transported legally. Liquid withdrawal valves cost around $100.

Propane tank valve summary

Valve

Purpose

Ballpark cost (US dollars)

Safety relief valve

Relieves excess pressure in tank

50-100

Fill valve

Filling tank with propane

30-60

Service valve

Controls propane flow to system

30

Vapor eliminator valve

Saves excess vapor when tank is being filled

30

Liquid withdrawal valve

Removes liquid propane from tank

100