The Belimo Z3050Q-E+CQKB24-S-LL is a ZoneTight QCV 3-way diverting zone valve assembly: a 1/2" NPT female forged brass ball valve with Cv 1 and linear flow, paired with the CQKB24-S-LL electrical fail-safe On/Off actuator at AC/DC 24 V that drives to 100% Open on power loss and carries one SPST auxiliary switch rated 1 A resistive @ DC 30 V.
The valve closes off against 40 psi, carries a 360 psi body pressure rating and handles chilled or hot water with up to 60% glycol from 36 to 212°F. Its compact body fits space restricted equipment, and the actuator snaps on by hand with no tools or linkage. The CQKB24-S-LL draws 2.5 W in operation, sizes at 5 VA for the transformer and runs 75 s per 90° stroke; its electrical fail-safe has a 5...20 s pre-charging time.
Best For
- Change-over and diverting duty on fan coil units and unit ventilators
- VAV reheat coils, duct coils and fin tube casing
- Radiant panels in closed chilled and hot water systems
- Space restricted installations in commercial buildings
- Interlock control, end position indication or fan startup from the built-in auxiliary switch
Warranty
5-year Belimo warranty covering ZoneTight valve and actuator components.
If the 212°F operating range is exceeded due to a boiler control failure, the valve will safely contain the hot water but the manufacturer warranty becomes invalid.
Key Features
Zero-leakage ball valve
Leakage rate 0% with a chrome plated brass ball, PTFE seat and EPDM O-rings.
3-way diverting, Cv 1
Linear flow characteristic through a 1/2 in. NPT female forged brass body; flow is possible in both directions.
High pressure capability
Body pressure rating 360 psi with 40 psi close-off and 40 psi maximum differential pressure.
Tool-free snap assembly
The actuator plugs onto the valve by hand and can be oriented in 180° increments.
Electrical fail-safe
Drives to 100% Open on power loss; fail-safe running time <60 s after a 5...20 s pre-charge.
Built-in auxiliary switch
One SPST auxiliary switch rated 1 A resistive @ DC 30 V for end position indication, interlock control or fan startup.
ZOT Supply is an authorized distributor of Belimo products.
Technical Specifications
Valve
| Valve type | ZoneTight QCV zone valve, 3-way, internal thread |
|---|---|
| Valve size | 1/2 in. [DN 15] |
| Pipe connection | Internal thread, NPT (female) |
| Flow pattern | 3-way diverting |
| Flow characteristic | Linear |
| Cv | 1 |
| Fluid | Chilled or hot water, up to 60% glycol |
| Fluid temperature range | 36...212°F [2...100°C] |
| Body pressure rating | 360 psi |
| Close-off pressure | 40 psi |
| Maximum differential pressure | 40 psi |
| Leakage rate | 0% |
| Flow direction | Both directions possible |
| Installation orientation | Upright to horizontal; not stem-down |
| 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 |
| Valve weight | 0.44 lb [0.2 kg] |
Actuator
| Actuator model | CQKB24-S-LL |
|---|---|
| Actuator type | Electrical fail-safe |
| Control | On/Off |
| 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 source UL | Class 2 Supply |
| Power consumption in operation | 2.5 W |
| Power consumption in rest position | 0.5 W |
| Transformer sizing | 5 VA |
| Auxiliary switch | 1x SPST, 1 A resistive @ DC 30 V |
| Electrical connection | 22 GA plenum cable, 3 ft [1 m], with 1/2 in. NPT conduit connector |
| Bridging time (PF) | 2 s |
| Pre-charging time | 5...20 s |
| Running time fail-safe | <60 s |
| Noise level, fail-safe | 35 dB(A) |
| Fail position | 100% Open |
| Angle of rotation | 90°, adjustable with mechanical stop |
| Running time (motor) | 75 s / 90° |
| Noise level, motor | 35 dB(A) |
| Position indication | Pointer |
| Overload protection | Electronic throughout 0...90° rotation |
| Electrical protection | Actuators are double insulated |
| Degree of protection IEC/EN | IP40 |
| Degree of protection NEMA/UL | NEMA 2 |
| Enclosure | UL Enclosure Type 2 |
| 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 |
| UL 2043 compliant | Suitable for use in air plenums per Section 300.22(C) of the NEC and Section 602 of the IMC |
| Ambient humidity | Max. 95% RH, non-condensing |
| Ambient temperature | 35...104°F [2...40°C] |
| Storage temperature | -40...176°F [-40...80°C] |
| Housing material | UL94-5VA |
| Actuator weight | 0.57 lb [0.26 kg] |
Assembly Dimensions
| Overall length (A) | 4.5 in. [114 mm] |
|---|---|
| Valve body length (B) | 2.0 in. [52 mm] |
| Overall height (C) | 3.8 in. [97 mm] |
| Pipe centerline to top (D) | 2.7 in. [69 mm] |
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 Z3050Q-E+CQKB24-S-LL?
The Z3050Q-E+CQKB24-S-LL has a Cv of 1 with a linear flow characteristic in a 3-way diverting pattern.
What close-off pressure does the Z3050Q-E+CQKB24-S-LL handle?
Close-off pressure is 40 psi, maximum differential pressure is 40 psi and the body pressure rating is 360 psi.
What is the fail position of the Z3050Q-E+CQKB24-S-LL?
The CQKB24-S-LL actuator drives to 100% Open when power is removed.
What power supply does the CQKB24-S-LL need?
Nominal voltage is AC/DC 24 V (AC 19.2...28.8 V / DC 21.6...28.8 V), 50/60 Hz; transformer sizing is 5 VA.
What is the auxiliary switch rating?
One SPST auxiliary switch rated 1 A resistive @ DC 30 V. Apply only AC line voltage or only UL Class 2 voltage to its terminals.
Why remove the actuator end stop clip?
The end stop clip must be removed from the actuator to get the 90° angle of rotation the change-over function needs.
How must the valve be installed?
Upright to horizontal in relation to the stem. Do not install it hanging with the stem pointing downward. A strainer is recommended.
What fluids and temperatures is the Z3050Q-E rated for?
Chilled or hot water with up to 60% glycol, 36...212°F [2...100°C], in closed systems.
Specifications sourced from Belimo Z3050Q-E technical data sheet (2024-12-17) and CQKB24-S-LL technical data sheet (2024-03-15); verified 2026-10-09.
- Valve Pattern:
- 3-Way
- Valve Size:
- 1/2 Inch
- Connection Type:
- NPT
- CV Rating:
- 1
- Actuator Type:
- Fail-Safe
- Voltage:
- 24VAC/DC
- Control Signal:
- On/Off
- Auxillary Switch:
- (1) SPST 1A @30VDC
