The Caleffi 549510A is a 4-in-1 combination hydraulic, air, dirt and magnetic separator with 4" ANSI B16.5 Class 150 flanged connections, rated for 247 gpm at a maximum working pressure of 150 psi. It installs between the heat source circuit and the distribution circuits of a hydronic heating or chilled water system to provide hydraulic, air, dirt and magnetic separation.
Caleffi specifies this series for hydronic heating and chilled water systems containing a primary production circuit with its own pump and a secondary user circuit with one or more distribution pumps, where pump interaction would otherwise cause abnormal variations in circuit flow rates and pressures. Caleffi states the separator should be sized to the greater of the primary or secondary circuit flow rate; this model is rated for 247 gpm. Source: 01249/22 NA, Operating principle and Hydraulic characteristics.
Key Features
Primary/Secondary Hydraulic Decoupling
A low pressure-loss zone lets the boiler circuit and the distribution circuits operate independently, so neither pump interferes with the other. Rated for 247 gpm.
Air Separation to Micro-Bubble Level
A stainless steel or HDPE coalescing element releases entrained air down to micro-bubble size and vents it automatically, achieving 100% removal to micro-bubble level.
Dirt Separation to 5 Micron
The same internal element and the vessel's low-velocity volume capture non-ferrous particulate down to 5 µm (0.2 mil), collecting it clear of the flow stream.
Neodymium Magnetic Ferrous Capture
A rare-earth magnet assembly sited outside the flow path removes magnetite and other ferrous debris with up to 100% efficiency and no added pressure drop, delivering 2-1/2 times the ferrous removal of a standard air and dirt separator.
Insulation Shell Included
Supplied with a rigid closed-cell expanded polyurethane foam shell under an embossed aluminum cover, rated to 220 °F and suitable for chilled water service without surface condensation.
Technical Specifications
| Product Line | SEP4 |
| Series | 5495 |
| Connection Size | 4" |
| Connection Type | ANSI Flange |
| Connection Style | Flanged |
| Separation Functions | Hydraulic, air, dirt and magnetic separation (4-in-1) |
| Rated Flow | 247 gpm |
| Fluid Volume | 8.0 gal |
| Air Separation Efficiency | 100% removal to micro-bubble level |
| Particle Separation Capacity | 5 µm (0.2 mil) |
| Ferrous Impurity Separation | Up to 100% removal |
| Magnet Type | Neodymium rare-earth |
| Maximum Working Pressure | 150 psi (10 bar) |
| Vessel Working Temperature Range | 32 - 270 °F (0 - 132 °C) |
| Working Temperature Range, Insulated | 32 - 220 °F (0 - 105 °C) |
| Suitable Fluids | Water and non-hazardous glycol solution to 50% |
| Body Material | Epoxy resin painted steel |
| Internal Element Material | 300 series stainless steel |
| Flange Standard | ANSI B16.5 Class 150 RF |
| Drain Valve Connection | 1" NPT Female |
| Insulation | Rigid closed-cell polyurethane foam shell with embossed aluminum cover, included |
| Magnet Assembly Part Number | 49684A |
| Product Weight | 120 lb |
Specifications on this page are taken from Caleffi North America technical brochure 01249/22 NA and the associated submittal and installation documents linked below. Last verified July 2026.
Documentation
Design Resources
Related Products
- Caleffi NA549102AM : SEP4 4" ANSI Flanged, ASME/CRN
- Caleffi 548102A : Hydro Separator 4" ANSI Flanged
- Caleffi 49684A : Magnet and Drywell for 3" to 6" SEP4 and 2", 2-1/2" DirtMag
- Caleffi 501502A : MAXCAL Automatic Air Vent 3/4" NPT Female
- Caleffi NA39589 : Ball Valve 3/4" Female-Female
Frequently Asked Questions
What does the Caleffi 549510A do in a hydronic system?
The Caleffi 549510A is a 4-in-1 combination hydraulic, air, dirt and magnetic separator with 4" ANSI B16.5 Class 150 flanged connections. It creates a low pressure-loss zone between the boiler circuit and the distribution circuits so that each pump works only against its own loop, which eliminates pump conflict without relying on closely spaced tees. It is rated for 247 gpm and holds 8.0 gallons.
How does the Caleffi 549510A differ from a plain hydraulic separator?
A plain hydraulic separator performs one function. The 549510A performs four in a single vessel: hydraulic separation, air separation to micro-bubble level, dirt separation to 5 microns, and magnetic capture of ferrous impurities. Caleffi rates the magnetic function at 2-1/2 times the ferrous removal performance of a standard air and dirt separator.
What flow rate is the Caleffi 549510A rated for?
Caleffi rates the 4" 549510A at 247 gpm with a fluid volume of 8.0 gallons. A hydraulic separator should be sized to the greater of the primary or secondary circuit design flow rate, not to the pipe size alone.
Is the Caleffi 549510A ASME code stamped?
No. The 549510A is rated for 150 psi maximum working pressure but is not ASME code stamped. Where a project specification calls for an ASME stamped and National Board registered vessel, use the corresponding Caleffi NA-prefix model.
Does the Caleffi 549510A come with insulation?
Yes. Flanged sizes through 4" are supplied with a rigid closed-cell expanded polyurethane foam shell under an embossed aluminum cover, rated for 32 to 220 °F. The shell also prevents surface condensation in chilled water service.
- Type:
- Hydraulic Separator
- Separation Functions:
- Hydraulic + Air + Dirt + Magnetic
- Product Line:
- SEP4
- Series:
- 5495
- Connection Style:
- Flanged
- ASME Code Stamped:
- No
- CRN Registered:
- No
- Insulation Included:
- Yes
- Connection Type:
- ANSI Flange
- Connection Size:
- 4 inch
- Max Operating Pressure:
- 150 psi
