The Caleffi 508013A is a HYGROCAL air vent with 1/8" NPT Threaded connections. Installed on radiators, it automatically releases accumulated air and its hygroscopic cartridge swells on contact with water to seal the vent.
Best for automatic air release at system high points.
Specifications sourced from Caleffi North America technical literature. Last reviewed July 2026.
Key Features
Hygroscopic Operation
Hygroscopic cartridge swells when wetted to positively seal the vent; replacement cartridge 508100A keeps the vent serviceable.
System Protection
Continuous automatic air release helps reduce oxygen-driven corrosion, trapped-air noise in emitters and cavitation at circulator pumps.
Technical Specifications
| Function | Automatic float air vent |
| Series | Caleffi HYGROCAL |
| Connection | 1/8 in NPT male |
| Body material | Brass |
| Maximum operating pressure | 150 psi |
| Medium temperature range | 40 - 212 °F |
| Finish | Chrome |
| Shipping Weight | 0.5 lb |
Documentation
Design Resources
Related Products
- Caleffi 508100A : HYGROCAL Replacement Cartridge
- Caleffi 502420 : ROBOCAL Air Vent 1/4" Metric Thread
- Caleffi 502630 : ROBOCAL Air Vent 3/8" Metric Thread
- Caleffi 502640 : ROBOCAL Air Vent 1/2" Metric Thread
Frequently Asked Questions
What does Caleffi 508013A do?
Caleffi 508013A is an air vent in the Caleffi HYGROCAL range. It automatically releases air that accumulates in the system, helping prevent oxygen-driven corrosion, trapped-air noise and pump cavitation.
What connection does Caleffi 508013A use?
It is supplied with 1/8" NPT Threaded connections. Other sizes and connection styles in the HYGROCAL range are listed under Related Products.
What are the pressure and temperature limits of Caleffi 508013A?
Maximum operating pressure is 150 psi, over a medium temperature range of 40 - 212 °F.
What is the warranty on Caleffi 508013A?
Caleffi covers this product under its standard two-year limited warranty against defects in material and workmanship from the date of shipment. ZOT Supply is an authorized Caleffi distributor.
- Product Type:
- Air Vent
- Series:
- HYGROCAL
- Connection Type:
- NPT Threaded
- Connection Size:
- 1/8 in
- Max Operating Pressure:
- 150 psi
- Medium Temperature Range:
- 40 - 212 deg F
- Body Material:
- Brass
