The Caleffi 551003A is a DISCAL air separator with 3/4" NPT Threaded connections. It is installed in the circuit to remove entrained air before it reaches pumps, control valves and heat exchangers.
Best for continuous removal of entrained microbubbles that a point air vent will not capture.
Specifications sourced from Caleffi North America technical literature. Last reviewed July 2026.
Key Features
Coalescing Air Separation
An internal medium coalesces microbubbles out of the flow stream and routes them to an automatic vent, removing air that a point vent alone will not capture.
Construction
Body material: Brass.
Rated Operating Envelope
Maximum operating pressure 150 psi, medium temperature range 32 - 250 °F.
Technical Specifications
| Function | Air separation |
| Series | Caleffi DISCAL |
| Connection | 3/4 in NPT |
| Body material | Brass |
| Maximum operating pressure | 150 psi |
| Medium temperature range | 32 - 250 °F |
| Suitable fluids | Water, glycol solution (max 50% glycol) |
| Air separation efficiency | 100% to micro-bubble level |
| Shipping Weight | 2.0 lb |
Documentation
Related Products
- Caleffi 551716 : DISCAL Air Separator Body Only
- Caleffi 551003AC : DISCAL Air Separator 3/4" NPT Threaded
- Caleffi 551005A : DISCAL Air Separator 3/4" NPT Threaded
- Caleffi 551005AC : DISCAL Air Separator 3/4" NPT Threaded
Frequently Asked Questions
What does Caleffi 551003A do?
Caleffi 551003A is an air separator in the Caleffi DISCAL range. It removes entrained air from the circulating fluid, protecting pumps, valves and heat exchangers.
What connection does Caleffi 551003A use?
It is supplied with 3/4" NPT Threaded connections. Other sizes and connection styles in the DISCAL range are listed under Related Products.
What are the pressure and temperature limits of Caleffi 551003A?
Maximum operating pressure is 150 psi, over a medium temperature range of 32 - 250 °F.
What is the warranty on Caleffi 551003A?
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 Separator
- Series:
- DISCAL
- Connection Type:
- NPT Threaded
- Connection Size:
- 3/4 in
- Air Separation Efficiency:
- 100% to micro-bubble level
- Max Operating Pressure:
- 150 psi
- Medium Temperature Range:
- 32 - 250 deg F
- Body Material:
- Brass
