The Series CARD combination air release/degassing valve provides three different venting operations in one unit. It releases air during system startup, provides continuous degassing during system operation and prevents pipeline vacuum in case of leaks or siphon. A self-guided, high-buoyancy float, in combination with an elastomer-sealed poppet, assures bubble-tight sealing after expelling air or gas. It is offered in a variety of corrosion-resistant thermoplastic materials in three sizes for a range of venting volume requirements.