One Way Valve (Gas)

A one way valve has an input and an output and stops gas from flowing back. It needs neither power nor a data cable; it has no port for either.

You will only find this version in older saves. In the game data no kit builds it any more. The Kit (Pipe Valve) from the Hydraulic Pipe Bender places the One Way Valve (Gas) instead, which is also called “One Way Valve (Gas)” in game. The difference: the new version has a switch (On) and only works while it is on. The old one always works.

What it does in the game code: every tick it fully equalises the input with the output, but only in that direction – gas flows as long as the input has more pressure, liquid as long as the input is fuller. Setting, Maximum and Ratio do appear in the logic list because all pipe devices inherit them. The valve never reads Setting, though, and without a data port no chip can reach it anyway.

Where a one way valve helps:

• Merges: two pumps fill the same store. Without a valve the stronger side pushes gas back into the weaker one.
• Exhaust lines: several devices feed exhaust into a shared line. One way valves keep it from running back into a device when the line backs up.
• Protecting a supply network in case a consumer line ever has more pressure than the supply.

Mind the direction when placing it – built the wrong way round it blocks exactly the path you want. You take it down with the wrench. How valves, regulators and pumps fit together is covered in Pumps, valves and pressure regulators: which part for what.