The Caleffi 31901A is a union tailpiece with a 3/4 in NPT connection, in brass for Caleffi AutoFill products, providing the union joint that lets the host valve or separator be installed and removed without cutting pipe.
Product data compiled from Caleffi North America technical documentation. Last reviewed July 2026.
Key Features
Service Without Cutting Pipe
The union joint lets the host valve or separator drop out of the line for service or replacement - no torch, no pipe cutter.
Factory-Machined Sealing Face
Genuine Caleffi machining ensures the union face seals reliably against the matching nut and washer.
Technical Data
| Function | Tailpiece |
|---|---|
| For product line | AutoFill |
| Description | 3/4 in MNPT Fitting |
| Connection type | NPT Threaded |
| Connection size | 3/4 in |
| Material | Brass |
Related Products
Frequently Asked Questions
It is the genuine fitting for Caleffi AutoFill products. Match your host model number and connection size before ordering.
It creates a break point in the piping so the valve or separator can be removed for service without cutting pipe or unsoldering joints.
- Type:
- Tailpiece
- For Product Line:
- AutoFill
- Connection Type:
- NPT Threaded
- Connection Size:
- 3/4 in
- Material:
- Brass