The Belimo B311+NRX24-3-T N4 is a 1/2 in. 3-way mixing/diverting characterized control valve (CCV), Cv 1.9, with a stainless steel ball and stem, assembled with the Belimo NRX24-3-T N4 non fail-safe actuator for on/off or floating point control on a 24 VAC/DC supply.
A TEFZEL® characterized disc gives the valve an A-port equal percentage, B-port modified for constant common port flow flow characteristic. Rated 600 psi body pressure and 200 psi close-off, for chilled or hot water, up to 60% glycol from 0...250°F [-18...120°C].
Best For
- Heating and cooling coils in air handling units
- Fan coil unit heating and cooling coils
- Unit ventilators
- VAV box reheat coils
- Bypass loops
- Hydronic systems with variable or constant flow
Warranty
This Belimo characterized control valve product carries a 5-year warranty on all components from the date of production, with the first two years unconditional.
Key Features
Characterized Disc
TEFZEL® disc produces an A-port equal percentage, B-port modified for constant common port flow flow characteristic.
On/Off or Floating Point
NRX24-3-T N4 accepts on/off or floating point control.
NEMA 4X Housing
Degree of protection NEMA 4X, IP66/67.
Pressure Ratings
600 psi body pressure rating, 200 psi close-off pressure.
Ball and Stem
Stainless steel ball, stainless steel stem, PTFE seat.
ZOT Supply is an authorized distributor of Belimo products.
Technical Specifications
| Valve: Belimo B311 | |
|---|---|
| Valve Size | 0.5" [15] |
| Fluid | chilled or hot water, up to 60% glycol |
| Fluid Temperature Range | 0...250°F [-18...120°C] |
| Body Pressure Rating | 600 psi |
| Close-Off Pressure (∆ps) | 200 psi |
| Flow | A-port: as stated in chart B-port: 70% of A–AB Cv |
| Flow Characteristic | A-port equal percentage, B-port modified for constant common port flow |
| Leakage Rate | 0% for A–AB, <2.0% for B–AB |
| Pipe Connection | Internal thread NPT (female) |
| Servicing | maintenance-free |
| Flow Pattern | 3-way Mixing/Diverting |
| Controllable Flow Range | 75° |
| Cv | 1.9 |
| Valve Body | Nickel-plated brass body |
| Stem | stainless steel |
| Stem Seal | EPDM (lubricated) |
| Seat | PTFE |
| Characterized Disc | TEFZEL® |
| O-ring | EPDM (lubricated) |
| Ball | stainless steel |
| Flow Rate @ 4 psi Pressure Drop | 3.8 GPM |
| Valve Weight | 0.59 lb [0.27 kg] |
| Actuator: Belimo NRX24-3-T N4 | |
|---|---|
| Nominal voltage | AC/DC 24 V |
| Nominal voltage frequency | 50/60 Hz |
| Nominal voltage range | AC 19.2...28.8 V / DC 21.6...28.8 V |
| Power consumption in operation | 2W |
| Power consumption in rest position | 0.2 W |
| Transformer sizing | 4 VA |
| Electrical Connection | Screw terminal (for 26...14 AWG wire), 1/2" NPT conduit connector |
| Overload Protection | electronic throughout 0...95° rotation |
| Direction of motion motor | selectable with switch 0/1 |
| Manual override | external push button |
| Angle of rotation | Max. 90° |
| Angle of rotation note | adjustable with mechanical stop |
| Running Time (Motor) | 90 s / 90° |
| Sound power level, motor | 45 dB(A) |
| Position indication | pointer |
| Power Source (UL) | Class 2 Supply |
| Degree of Protection (IEC/EN) | IP66/67 |
| Degree of Protection (NEMA/UL) | NEMA 4X |
| Housing | UL Enclosure Type 4X |
| Agency Listing | cULus acc. to UL60730-1A/-2-14, CAN/CSA E60730-1:02, CE acc. to 2014/30/EU and 2014/35/EU |
| Quality Standard | ISO 9001 |
| Ambient humidity | Max. 100% RH |
| Ambient temperature | -22...122°F [-30...50°C] |
| Ambient temperature note | -40...122°F [-40...50°C] for actuator with integrated heating |
| Storage temperature | -40...176°F [-40...80°C] |
| Servicing | maintenance-free |
| Housing material | Die cast aluminium and plastic casing |
| Actuator Weight | 1.7 lb [0.79 kg] |
Compatible Accessories
Belimo accessories for the B311+NRX24-3-T N4, available from ZOT Supply.
Electrical Accessories
Documentation
Belimo B311+NRX24-3-T N4 Technical Data Sheet (Valve + Actuator)Belimo N4 Heater 24V -H Technical Data SheetCCV Installation InstructionsCharacterized Control Valve (CCV) Technical DocumentationCCV Accessories DocumentationElectronic Valve Applications GuideBelimo Ball Valve Master FormatSuccess Story: Habitat for Humanity Home with Belimo CCVSuccess Story: New York PostSuccess Story: Sonoma State University RenovationSuccess Story: Western Wyoming Community CollegeFrequently Asked Questions
What is the Cv of the Belimo B311+NRX24-3-T N4?
The B311 valve is rated Cv 1.9. At a 4 psi pressure drop it passes 3.8 GPM of water.
What size and pipe connection does the B311+NRX24-3-T N4 use?
1/2 in. (0.5" [15]) with internal thread NPT (female) connections.
Is the B311+NRX24-3-T N4 fail-safe?
No. The NRX24-3-T N4 is a non fail-safe actuator.
What control signal does the B311+NRX24-3-T N4 accept?
The NRX24-3-T N4 accepts on/off or floating point control.
What power supply does the B311+NRX24-3-T N4 need?
Nominal voltage AC/DC 24 V. Transformer sizing: 4 VA.
What warranty does the B311+NRX24-3-T N4 have?
A Belimo 5-year warranty on all components from the date of production, with the first two years unconditional.
What accessories are available for the B311+NRX24-3-T N4?
ZOT Supply carries these compatible Belimo accessories: S1A (Auxiliary switch 1x SPDT add-on); S2A (Auxiliary switch 2x SPDT add-on); P140A GR (Feedback potentiometer 140 Ω add-on, grey); P1000A GR (Feedback potentiometer 1 kΩ add-on, grey); P10000A GR (Feedback potentiometer 10 kΩ add-on, grey); P2800A GR (Feedback potentiometer 2.8 kΩ add-on, grey); P500A GR (Feedback potentiometer 500 Ω add-on, grey); P5000A GR (Feedback potentiometer 5 kΩ add-on, grey).
What is the close-off pressure of the B311+NRX24-3-T N4?
200 psi close-off pressure, with a 600 psi body pressure rating.
What fluids can the B311+NRX24-3-T N4 control?
Chilled or hot water, up to 60% glycol, fluid temperature range 0...250°F [-18...120°C].
Specifications per Belimo B311 technical data sheet (2026-02-07) and Belimo NRX24-3-T N4 technical data sheet (2025-12-23); flow rate per Belimo CCV Technical Documentation (P10419 - 09/13); warranty per Belimo CCV Master Format, Section 230923.11. Content updated November 2026.
- Valve Pattern:
- 3-Way
- Valve Size:
- 1/2 Inch
- CV Rating:
- 1.9
- GPM:
- 3.8 @ 4 psi
- Material:
- Stainless Steel
- Actuator Type:
- Non Fail-Safe
- Voltage:
- 24VAC/DC
- Control Signal:
- On/Off, Floating Point
- Auxillary Switch:
- None
- Enclosure:
- NEMA 4X
