These connect directly. CGA-320 CO2 cylinder valve mates with CGA-320 (flat seat detail) without an adapter. Sealing method, the real-world trap, and the exact part to buy.
Updated 05 September 2026.
Connect CGA-320 CO2 cylinder valve to CGA-320 (flat seat detail)
How to join 0.825"-14 NGO RH and 0.825"-14 NGO RH, flat nipple, and what stops it leaking.
These connect directly. CGA-320 CO2 cylinder valve mates with CGA-320 (flat seat detail) without an adapter.
The two ends
- End A
- CGA-320 CO2 cylinder valve (0.825"-14 NGO RH)
- End B
- CGA-320 (flat seat detail) (0.825"-14 NGO RH, flat nipple)
- A seals on
- nylon or fibre washer inside the nut against the valve outlet
- B seals on
- flat nylon or fibre washer inside the nut against the flat valve seat
- Part needed
- none, direct fit
CGA-320 and the flat-seat CGA-320 detail describe the same connection: a 0.825-14 NGO right-hand nut sealing on a flat washer against a flat valve seat. Any CGA-320 regulator fits any CGA-320 CO2 cylinder.
The flat seat and its washer are what make CGA-320 seal, so a missing or hardened washer, not a loose nut, is the usual cause of a hiss. Keep a spare fibre washer and do not overtighten the nut to chase a leak.
Related connections
Questions and answers
Connect CGA-320 CO2 cylinder valve to CGA-320 (flat seat detail)?
These connect directly. CGA-320 CO2 cylinder valve mates with CGA-320 (flat seat detail) without an adapter.