Hoffman 401475 1/8″ Straight Air Vent for Radiator Valve

The Hoffman 401475 air vent, also identified as the 508 radiator water vent valve, is engineered for reliable venting of hot‑water steam heating convector systems. Featuring a 1/8″ NPT male straight shank, this vent integrates a disc‑type mechanism with a built‑in check valve, allowing both automatic and manual operation to release trapped air while preventing backflow.

Designed as the modern replacement for the classic Hoffman No. 500 and compatible with B&G 17‑JR and 17‑SR models, the vent is rated for a maximum pressure of 50 lb. Its compact construction ensures easy installation in tight spaces, and the robust check valve maintains system efficiency by sealing after venting. This update delivers the same trusted performance with improved materials for extended service life.