The Caleffi 337221A is a Manual air vent with a 1/4 in NPT connection and a composite/brass body, used to manually release air from the high points of hydronic heating and cooling systems.
Product data compiled from Caleffi North America technical documentation. Last reviewed June 2026.
Key Features
Manual Air Release
Allows controlled manual venting of air from system high points.
Compact Build
Durable construction for reliable service at manifolds and other high points.
1/4 In Npt Connection
1/4 in NPT connection sized for the application.
Composite/Brass Construction
Composite/Brass body with stainless and EPDM internal components for hydronic service.
Technical Data
| Function | Manual air vent |
|---|---|
| Series | Caleffi Manual |
| Connection | 1/4 in NPT |
| Body material | Composite/Brass |
| Maximum operating pressure | 150 psi |
| Medium temperature range | 40 - 212 °F |
Documentation
Instruction sheetRelated Products
Frequently Asked Questions
At the high points of a hydronic system such as manifolds, air separators and pump locations, where air naturally collects.
150 psi maximum operating pressure with a medium temperature range of 40 - 212 °F.
- Type:
- Air Vent
- Series:
- Manual
- Body Material:
- Composite/Brass
- Connection Type:
- NPT Threaded
- Connection Size:
- 1/4 in
