The Belimo Z3100QS-J is a 1" sweat, 3-way diverting ZoneTight zone valve (valve only): a forged brass ball valve with Cv 4.4, 0% leakage and 40 psi close-off for switching and 2-point control of chilled or hot water. It accepts Belimo CQB(X) non fail-safe or CQKB(X) electronic fail-safe actuators, sold separately.
Suited to large commercial buildings where higher close-off and the ability to change flow are needed. The valve fits space-restricted areas and assembles without tools: the actuator snaps onto the valve by hand, and its mounting orientation can be turned in 180° increments.
Specifications per Belimo Z3100QS-J technical data sheet rev 2025-01-09. Reviewed 2026-10-09.
Best For
- Switching functions and 2-point control on the water side of air-handling units and heating systems
- Change-over (3-way diverting) duty in closed chilled and hot water systems
- Unit ventilators, fan coil units, VAV reheat coils, fin tube casing, radiant panels and duct coils
- Pairing with a separately purchased Belimo CQB(X) or CQKB(X) ZoneTight actuator
Warranty
Belimo ZoneTight valves carry a 5-year warranty. If fluid temperature exceeds the 212°F operating range because of a boiler control failure, the valve will safely contain the hot water, but the manufacturer warranty becomes invalid and valve and actuator replacement is at the expense of others.
Key Features
3-way diverting ball valve
Diverting flow pattern for change-over duty, linear flow characteristic, Cv 4.4 and 0% leakage.
40 psi close-off
Close-off pressure 40 psi, maximum differential pressure 40 psi, body pressure rating 360 psi.
Actuator choice
Fits Belimo CQB(X) non fail-safe and CQKB(X) electronic fail-safe actuators with tool-free snap assembly.
Forged brass body
Brass stem, chrome plated brass ball, PTFE seat with EPDM O-rings.
Sweat connection
1" sweat ends; flow in both directions; install upright to horizontal.
ZOT Supply is an authorized distributor of Belimo products.
Technical Specifications
Valve: Belimo Z3100QS-J
| Valve size | 1" [25] (DN 25) |
| Flow pattern | 3-way Diverting |
| Pipe connection | Sweat |
| Cv | 4.4 |
| Fluid | chilled or hot water, up to 60% glycol |
| Fluid temp range (water) | 36...212°F [2...100°C] |
| Body pressure rating | 360 psi |
| Close-off pressure Δps | 40 psi |
| Differential pressure Δpmax | 40 psi |
| Flow characteristic | linear |
| Leakage rate | 0% |
| Operating mode | change-over zone valve adjusted by a rotary actuator controlled by an on/off signal |
| Flow direction | both directions possible |
| Flow setting | remove the end stop clip at the actuator to get the 90° angle of rotation needed for the change-over functionality |
| Installation orientation | upright to horizontal (in relation to the spindle); not in a hanging position with the stem pointing downwards |
| Actuator mounting | tool-free snap assembly; mounting orientation selectable in 180° increments |
| Water quality | keep free from particle debris; installation of a suitable strainer is recommended |
| Servicing | maintenance-free |
| Valve body | forged brass |
| Stem | brass |
| Stem seal | EPDM O-ring |
| Seat | PTFE, O-Ring EPDM |
| O-ring | EPDM (lubricated) |
| Ball | chrome plated brass |
| Suitable actuators | Non Fail-Safe CQB(X); Electronic fail-safe CQKB(X) |
| Valve weight | 0.57 lb [0.26 kg] |
| California Proposition 65 | WARNING: This product can expose you to lead which is known to the State of California to cause cancer and reproductive harm. For more information go to www.p65warnings.ca.gov |
Documentation
FAQ
What is the Cv of the Belimo Z3100QS-J?
Cv 4.4, with a linear flow characteristic and 0% leakage.
What close-off pressure does the Z3100QS-J handle?
40 psi close-off, 40 psi maximum differential pressure and a 360 psi body pressure rating.
Does the end stop clip need to be removed on the Z3100QS-J?
Yes. Remove the end stop clip at the actuator to get the 90° angle of rotation needed for the change-over functionality.
Which actuators fit the Z3100QS-J?
Belimo CQB(X) non fail-safe and CQKB(X) electronic fail-safe ZoneTight actuators, sold separately.
What fluids can the Z3100QS-J control?
Chilled or hot water, up to 60% glycol, from 36 to 212°F [2 to 100°C].
- Valve Pattern:
- 3-Way
- Valve Size:
- 1 Inch
- Connection Type:
- Sweat
- CV Rating:
- 4.4
- Max Close-Off Pressure:
- 40 psi
- Max Operating Pressure:
- 360 psi
- Medium Temperature Range:
- 36-212 °F
- Body Material:
- Forged Brass
- Actuator Type:
- Valve Only
