The Caleffi 437516 is a compression fitting for 1/2 in hard copper tube, with an o-ring seal and a 3/4 in straight-thread female nut. It connects copper pipe to the 3/4 in conical pipe connection on the Caleffi 301, 338 and 339 series radiator valves.
Best for connecting 1/2 in hard copper to a Caleffi radiator or panel radiator valve without soldering at the valve.
Specifications from Caleffi datasheets 01036/23 NA and 01009/23 NA, 437 series fittings. Valve compatibility per the explicit statement in 01009/23 NA and the 301 series fittings listing in 01036/23 NA. Reviewed August 2026.
Key Features
O-Ring Compression Seal
Seals on 1/2 in hard copper with an o-ring rather than a metal-to-metal olive, so the joint is made and remade without heat and without dressing the tube end.
3/4 in Straight-Thread Female Nut
Mates to the 3/4 in male conical pipe connection on the Caleffi 301, 338 and 339 series radiator valves, the families this fitting is documented against.
Wide Temperature Range
Rated -13 to 250°F (-25 to 120°C) at 150 psi (10 bar), well beyond the working range of the valves it serves.
Chrome Plated
Chrome-plated finish matching the exposed valve bodies, suitable for visible radiator connections.
Technical Specifications
| Product Type | Fitting |
| Series | 437 Series |
| Connection type | Compression |
| Pipe connection | 1/2 in hard copper compression |
| Valve connection | 3/4 in straight-thread female nut |
| Seal | O-ring |
| Finish | Chrome plated |
| Max. working pressure | 150 psi (10 bar) |
| Temperature range | -13 to 250°F (-25 to 120°C) |
| Documented valve families | Caleffi 301, 338 and 339 series |
Documentation
Related Products
- Caleffi 681503A : PEX Fitting 3/8" Nominal
- Caleffi NA10262 : Adapter Kit to 1/2" Sweat
- Caleffi NA10313 : Adapter Kit to 1/2" Male NPT
- Caleffi 387127 : Universal Radiator Tool
Frequently Asked Questions
What is the Caleffi 437516?
A compression fitting that connects 1/2 in hard copper tube to a Caleffi radiator valve. It has a 1/2 in compression end with an o-ring seal and a 3/4 in straight-thread female nut.
Which valves does the Caleffi 437516 fit?
The Caleffi 301, 338 and 339 series. Caleffi datasheet 01009/23 NA names the 338 and 339 series specifically, and 01036/23 NA lists this fitting for the 301 series.
Does the Caleffi 437516 work with soft copper or PEX?
It is specified for 1/2 in hard copper. For PEX use the 681 series universal PEX fittings; for PEX-AL-PEX use the 682 series.
What are the pressure and temperature limits?
150 psi (10 bar) maximum working pressure over a range of -13 to 250°F (-25 to 120°C).
- Product Type:
- Fitting
- Product Family:
- Fittings and Accessories
- Series:
- 437 Series
- Connection Type:
- Compression
- Connection Size:
- 1/2 in
- Fits Series:
- 301 Series
- Fits Series:
- 338/339 Series
- Max Operating Pressure:
- 150 psi (10 bar)
- Max Medium Temperature:
- 250 deg F (120 deg C)
