The check valve is often referred to as a Thomas Valve. This piece goes into the gas intake of a coupler. This allows gas to flow through the coupler and into the keg. However, it keeps beer from flowing backwards into the gas line. Gas lines aren’t cleaned so it is critical to keep beer out of them.
You may see opaque gas lines from time to time. An opaque gas line won’t allow you to see if bacteria is growing in it. One person suggested to us once that they had opaque lines on a system for 10 years with no issue. We just have to chuckle at that because how would one know there is no issue if it is opaque. Further, bacteria and a host of other organisms grow in oxygen AND non oxygen environments.
Only use gas lines you can see through and always make sure there is a check valve to keep beer out of it. If you do see bacteria growing in the gas line it is cheaper to replace it than to continue pushing bacterial gas into your beer.
Don’t hesitate to contact us if you have any questions about this or any other part we carry. We want to help you get your order right the first time and to keep your project underway.