CO2 Check valve

Why is a CO₂ check valve so important?
A CO₂ check valve is a crucial element in a CO₂ injection system. It protects all the devices behind it, like e.g. the pressure reducer, solenoid valve or the needle valves of CO₂ distributors from creeping water that would leave corrosion or deposits and thus impair their function or even render them altogether useless.

Why does water creep into the CO₂ injection system?
It's important to know that water creeps into the hose in any CO₂ injection systems when the CO₂ feed is shut off. Since CO₂ dissolves in water, the carbon dioxide still present in the hose dissolves in water, too, since the hose has water contact on one side. Bit by bit, this creates a negative pressure that invariably sucks water into the hose. If all the CO₂ in the hose is dissolved, the entire hose line is full of water. This phenomenon urgently calls for a CO₂ check valve that is positioned in the line between the last device and the diffusor/flipper.

Will I require a CO2 check valve in any case?

Some of the AQUA-NOA CO₂ components like e. g. the pressure reducer, solenoid valves or distributors are available with an integrated check valve.
Alternatively you can use the separate check valves on offer here, which are mounted in the CO₂ hose line.
You should never run a CO₂ injection system without a CO₂ check valve, though!

AQUA-NOA CO₂ check valve - variants

Basic, plastic
Standard 4/6 mm hose connection on both sides, with arrow marking the flow direction

Basic, metal
Standard 4/6 mm hose connection on both sides, with arrow marking the flow direction

Profi, metal
Standard 4/6 mm hose connection on both sides, with union nut and arrow marking the flow direction

Nano-Line, metal
Standard 4/6 mm hose connection on both sides, with union nut and arrow marking the flow direction