The Caleffi 301241 is a straight diverter valve for one-pipe panel radiators, 1/2 in radiator connection x 3/4 in conical pipe connection. It diverts 30 to 50 percent of loop flow through the radiator, factory-set at 35 percent, with an integral thermal-break check device.
Best for single-pipe loop systems where each radiator is teed off a common circuit.
Specifications sourced from Caleffi North America technical literature. Last reviewed July 2026.
Key Features
One-Pipe Diverter Operation
On a single-pipe loop the valve diverts part of the circuit flow into the radiator and returns it to the same main, so each emitter can be controlled without separate supply and return piping.
Adjustable Bypass, 30% to 50%
The bypass is field-adjustable to send 30 to 50 percent of loop flow through the radiator, factory-set at 35 percent, allowing output to be matched to the room.
Thermal-Break Check Device
An integral check prevents gravity circulation through the radiator when the zone is satisfied, avoiding unwanted heat gain in the off cycle.
Technical Specifications
| Product Type | Radiator Diverter Valve |
| Connections | 1/2 in radiator connection x 3/4 in conical pipe connection |
| Body Style | Straight |
| System Type | One-Pipe |
| Maximum operating pressure | 150 psi (10 bar) |
| Medium temperature range | 40 to 212 deg F (5 to 100 deg C) |
| Series | Straight Version |
| Shipping Weight | 0.5 lb (approx.) |
Documentation
Related Products
- Caleffi 301341 : Angled Diverter Valve, One-Pipe
- Caleffi 301140 : Angled Isolation Valve, Two-Pipe
- Caleffi 437516 : Compression Fitting 1/2 in Copper
- Caleffi 449740 : Wall-Covering Plate 40-50 mm
Frequently Asked Questions
How does Caleffi 301241 work on a one-pipe system?
On a single-pipe loop the valve diverts part of the circuit flow through the radiator and returns it to the same main, so each emitter can be controlled without separate supply and return piping.
Can the bypass on Caleffi 301241 be adjusted?
Yes. The bypass is field-adjustable to send 30 to 50 percent of loop flow through the radiator and is factory-set at 35 percent. An integral thermal-break check device prevents gravity circulation when the zone is satisfied.
What are the pressure and temperature limits of Caleffi 301241?
Maximum operating pressure is 150 psi (10 bar), over a medium temperature range of 40 to 212 deg F (5 to 100 deg C).
What is the warranty on Caleffi 301241?
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:
- Radiator Diverter Valve
- Product Family:
- Connection Valves
- Series:
- Straight Version
- Connections:
- 1/2 in radiator connection x 3/4 in conical pipe connection
- Body Style:
- Straight
- System Type:
- One-Pipe
- Max Operating Pressure:
- 150 psi (10 bar)
- Medium Temperature Range:
- 40 to 212 deg F (5 to 100 deg C)