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CGA-320 CO2 cylinder valve (0.825"-14 NGO RH)

Where 0.825"-14 NGO RH is used, its real dimensions, and how to connect it to other keg fittings.

Published dimensions

Designation
0.825"-14 NGO RH
Size / thread
0.825"-14 NGO (National Gas Outlet), right hand
Fitting form
cylinder valve outlet nut, external
Seals on
nylon or fibre washer inside the nut against the valve outlet
Rating / role
the North American CO2 cylinder connection, on refillable tanks up to about 1800 psi

Used on: the outlet of refillable CO2 cylinders across the US, Canada and Australian soda tanks; the regulator inlet nut screws onto it.

CGA-320 is a nut, not a thread you tape. It seals on a captive nylon or fibre washer inside the nut, so a missing or hardened washer is the usual cause of a hissing inlet. It is right hand, unlike some fuel gas connections, and is not interchangeable with the European W21.8.

Flare fittings seal on the 45 degree flare face and must never be taped. Push-in fittings seal on an O-ring against the tube wall and need the tube cut square. Barbs seal under a worm clamp. Getting the sealing method right matters more than the thread label, because most homebrew leaks are a taped flare or an unclamped barb.

Connect this fitting

Connect CGA-320 CO2 cylinder valve to W21.8 CO2 cylinder valveneeds an adapterConnect CGA-320 CO2 cylinder valve to G5/8 regulator inletneeds an adapterConnect TR21-4 soda cylinder valve to CGA-320 CO2 cylinder valveneeds an adapterConnect CGA-320 CO2 cylinder valve to 1/4" NPTneeds an adapterConnect CGA-580 nitrogen / beer-gas cylinder valve to CGA-320 CO2 cylinder valvenot compatibleConnect 16g threaded CO2 cartridge to CGA-320 CO2 cylinder valvenot compatibleConnect M10x1 CO2 cartridge thread to CGA-320 CO2 cylinder valveneeds an adapter

Sources: CGA-320 CO2 cylinder valve outlet thread reference (0.825in-14 NGO, RH) ยท CO2Art guide to cylinder connections (CGA320, W21.8, DIN477, BS341, G5/8, TR21-4)