By Jason Broderick
LP Gas Valve on Propane Tank Safety
Because in our store, we provide replacement parts for barbeque grills and in South Florida we provide repair service for all types of barbecues I often get questions and complaints about the safety features in the consumer-sized 20 lb liquid propane tank. The new LP tank canisters have several safety features required by law. Improper use of an LP tank can cause difficulty with your gas grill.
LP Tank Relief Valve
The safety relief valve is one of the most important and vital valves on any LP Gas container and it is something that should never require any attention from you. All propane tanks and cylinders are required by law to be fitted with pressure relief devices designed to relieve excess pressure. The function of a safety relief valve is to allow the tank to relieve pressure built up during excessive heat.
How Propane Relief Valves Work?
Relief valves are held closed by the force of a powerful spring. As long as the pressure inside the tank is less than that of the spring, the valve will remain closed. If tank pressure rises the valve will open resulting in a hissing sound outside the tank as small amounts of gas is released. If the pressure in the tank rises significantly higher than that of the spring, the valve will fully open. If this happens the valve makes a loud “pop” sound before gas is released. A full release is incredibly rare in my experience. In Florida we have some of the hottest weather in the country and the most we get is a little release when the liquid propane expands from outside heat. Propane tanks should be maintenanced every 12 years or as needed and the valve should never be tampered with by anyone who is not licensed to work with gas
A relief valve that is sealed shut will not allow the tank to vent excess pressure if it is overfilled or the pressure inside the tank exceeds the working pressure of the container. In a case where the tank is unable to vent to the outside let the propane company or LPG professional handle any problems with the safety relief valve.
You are an adult, please be responsible for your actions. Do not attempt to perform maintenance on gas appliances that should be performed by licensed professionals.
Important Safety Processes to Remember:
A LP Container will respond to heat by releasing some pressure. This means that on a very hot day your gas contaner may release some propane into the atmosphere releasing pressure caused by expansion. You LP tank must be kept in a well ventilated area because of this release function. Gas that is not able to dissipate into the atmosphere will hang around susceptible to a spark. Propane is heavier than air and will settle to the floor or the lowest point in the area. If your gas line valve or liquid propane tank is inside an outdoor kitchen, please review the built in barbeque grill manufacturers materials regarding ventilation of your outdoor kitchen. Generally at least two vents must be built in low to your grill island to allow a cross breeze that will carry gas fumes out of the enclosure.
Over-Fill OPD Valve Information
Before any propane cylinder (4 to 40#) can be filled with propane, the cylinder must have an OPD valve installed on the tank. When filling a propane bottle equipped with an OPD valve, the flow of gas should stop immediately when the overfill protection mechanism closes. Propane OPD valves operate inside the bottle and are activated as the liquid propane in the cylinder rises to a level that pushes a float upward stopping the flow of gas into the bottle. This action is similar to that of a float valve in a toilet; once the water in the bowl rises to a certain level, the flow of water stops. Propane bottles with overfill prevention valves have a triangular hand wheel at the top of the valve itself. The hand wheel connecting to the valve stem is tamperproof and is not interchangeable with older LP tanks. The OPD valve was not designed as a tool to let the bottle filler know when the bottle has reached its capacity but as a secondary safety mechanism. Bottles equipped with OPD valves should still to be filled by weight as required by law.
Check Valve — Low or No Gas Flow
I get more service requests for low heat output than any other consistent complaint. If you are experiencing low or no heat due to gas flow and you have determined there are no leaks (spray all fittings/joinings with soupy water looking for bubbles caused by leaking gas), you may need to reset the check valve.
Reset The Check Valve:
-Turn the LP container completely off.
-Disconnect the LP container from the grill.
-Turn the gas BBQ Grill valves to the highest setting.
-Now leave it alone for a few minutes while any residual gas and pressure is released from the gas lines, venturis and barbeque burners.
-Turn the barbecue grill completely off.
-Reattach the LP container.
-Turn the LP tank valve the the on position by turnng very, very slowly for the first two rotations.
-This will allow the gas to slowly fill the barbeque without blasting through the valve, putting the LP tank in check.
The check valve is designed to gauge the pressure of the gas as it leaves the propane cylinder. Because the gas grill should have all valves in the “off” position when the gas is turned on the pressure stops at the valve and is re-checked by the valve at the tank. If there is a leak or if the grill control valves are in the “on” position pressure is released and the pressure checked at the valve is different. When this happens the check valve is designed to stop gas flow through the valve.
The problem with the check valve is that it is very sensitive and when a tank is full, with the additional pressure of the OPD float pushing on the liquid, the gas can push through the check valve so strongly it checks the check valve by mistake. This happens frequently. If your BBQ is in good shape but you are not getting the heat you are accustomed to, often the check valve in your LP tank is to blame. Follow the steps above and get into the habit of turning the tank on slowly.
About the Author: Grill-Repair.com services all brands, all make and model of BBQ grill. In Florida we have on-site crews to repair barbecues and from our grill parts site we stock many replacement grill parts to help repair your barbeque grill. If you have any questions or need any assistance feel free to contact us anytime or access information on our blog site at: http://www.grill-repair.com/blog
Source: isnare.com
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