Variations

• There are kits that just come with a check valve that's threaded; you must shut off the system you're running by isolating the valve, removing the old valve and installing the new one. There's also a type that comes with clamps so you can just place the coupler over the edge of an open-ended pipe and clamp it down. This application is mainly used for sump pumps.
  
  

Types

• Check valve kits tell you which applications they support, but occasionally you'll need to figure out which one works best for you. There are different styles for gases and liquids. You will need to consider the pressure at which your operating as each check valve will be rated at different maximum pressures.
  
  

Purchase

• You can find inline check valve kits at most hardware stores. You can also get them online, but when purchasing something that depends so much on size and durability, it may be best to purchase one that you can see and feel first-hand.