ZONE225N-80+ZONE24NC-S Overview
The Belimo ZONE225N-80+ZONE24NC-S is a 2-way, 1 in. NPT on/off zone valve assembly that pairs the ZONE225N-80 forged brass valve body (Cv 8, 20 psi close-off) with the ZONE24NC-S AC 24 V normally closed spring return actuator and one built-in SPST auxiliary switch.
It is built for fan coil units, baseboards and other hydronic applications where fail-safe operation on 2-wire control is required, in systems with variable or constant flow, and handles chilled or hot water with up to 50% glycol from 32 to 212°F.
When power is removed, the actuator spring returns the valve to its closed position. The actuator runs on AC 24 V, 50/60 Hz, draws 6.5 W in operation and connects with 18 in. wire leads.
Best For
- Fan coil units, baseboards and other hydronic terminal equipment
- Applications that need fail-safe operation on 2-wire control
- Hydronic systems with variable or constant flow
- Chilled or hot water service with up to 50% glycol
- Low-voltage AC 24 V thermostat control circuits
- Projects that need a built-in auxiliary switch for an auxiliary circuit
Warranty
The Belimo ZONE225N-80+ZONE24NC-S carries a 2-year Belimo warranty.
Key Features
Fail-Safe Spring Return
The ZONE24NC-S actuator is normally closed: when power is removed, the spring returns the valve closed.
Simple On/Off Control
AC 24 V, 50/60 Hz on/off control with 6.5 W in operation, 90° rotation and 18 in. wire leads.
Forged Brass Valve Body
300 psi body pressure rating, Cv 8, 20 psi close-off and ANSI Class III 0.1% leakage.
Manual Override
Hand lever manual override for manual opening; the lever unlocks automatically when power is applied. Mechanical position indication is integrated.
Built-In Auxiliary Switch
1 x SPST, 0.4 A resistive (0.4 A inductive) @ AC 24 V.
NPT End Connections
1 in. [DN 25] NPT female ends.
ZOT Supply is an authorized distributor of Belimo products.
Technical Specifications
| Valve (ZONE225N-80) | |
|---|---|
| Valve model | ZONE225N-80 |
| Valve size | 1 in. [DN 25] |
| Flow pattern | 2-way |
| Flow characteristic | On/off |
| Cv | 8 |
| Fluid | Chilled or hot water, up to 50% glycol |
| Fluid temperature range | 32 to 212°F [0 to 100°C] |
| Body pressure rating | 300 psi |
| Close-off pressure | 20 psi |
| Leakage rate | ANSI Class III 0.1% |
| Valve body | Forged brass |
| Housing seal | EPDM |
| Stem | Stainless steel |
| Seat | EPDM |
| Pipe connection | NPT female ends |
| Valve weight | 1.32 lb [0.60 kg] |
| Actuator (ZONE24NC-S) | |
| Actuator model | ZONE24NC-S |
| Actuator type | Spring return, on/off |
| Normal position | Normally Closed (NC) |
| Nominal voltage | AC 24 V |
| Nominal voltage frequency | 50/60 Hz |
| Power consumption in operation | 6.5 W |
| Transformer sizing | 7 VA (class 2 power source) |
| Auxiliary switch | 1 x SPST, 0.4 A resistive (0.4 A inductive) @ AC 24 V |
| Electrical connection | 18 in. wire leads |
| Manual override | Hand lever |
| Angle of rotation | 90° |
| Noise level, motor | 35 dB(A) |
| Noise level, fail-safe | 35 dB(A) |
| Position indication | Mechanical, integrated |
| Degree of protection IEC/EN | IP20 |
| Degree of protection NEMA/UL | NEMA 1 |
| Enclosure | UL Enclosure Type 1 |
| Agency listing | CE, cULus |
| Quality standard | ISO 9001 |
| Ambient temperature | 32 to 104°F [0 to 40°C] |
| Storage temperature | -40 to 176°F [-40 to 80°C] |
| Ambient humidity | Max. 95% RH, non-condensing |
| Servicing | Maintenance-free |
Documentation
Frequently Asked Questions
What is the Cv and close-off pressure of the Belimo ZONE225N-80+ZONE24NC-S?
The ZONE225N-80+ZONE24NC-S has a Cv of 8 in a 1 in. 2-way valve body, a 20 psi close-off pressure, a 300 psi body pressure rating and ANSI Class III 0.1% leakage.
What happens to the Belimo ZONE225N-80+ZONE24NC-S when power is lost?
The ZONE24NC-S is a normally closed spring return actuator. When power is removed, the spring returns the valve to its closed position.
What power supply does the ZONE24NC-S actuator need?
AC 24 V, 50/60 Hz. It draws 6.5 W in operation, is sized at 7 VA (class 2 power source) for transformer selection and connects with 18 in. wire leads.
What is the auxiliary switch rating on the Belimo ZONE225N-80+ZONE24NC-S?
One built-in SPST auxiliary switch rated 0.4 A resistive (0.4 A inductive) @ AC 24 V, wired on two red leads to the auxiliary circuit.
Can the Belimo ZONE225N-80+ZONE24NC-S be opened manually?
Yes. The ZONE24NC-S has a hand lever manual override. Moving the manual opening lever to the locked position opens the valve, and the lever unlocks automatically when power is applied.
How should the Belimo ZONE225N-80+ZONE24NC-S be installed?
Install the valve vertically or horizontally, but not upside down. Flow is from port A to port B, and the valve must be installed so the paddle closes against the direction of flow. The 2-way valve can go on the supply or the return, following the flow arrow on the valve body.
Specifications verified against Belimo technical data sheet ZONE225N-80+ZONE24NC-S (2022-01-12), Belimo ZONE225N-80 valve technical data sheet (2023-01-10) and Belimo installation instructions 70264-00001E. Reviewed 2026-10-09.
- Valve Pattern:
- 2-Way
- Valve Size:
- 1 Inch
- Connection Type:
- NPT
- CV Rating:
- 8
- Actuator Type:
- Fail-Safe
- Voltage:
- 24VAC
- Control Signal:
- On/Off
- Auxillary Switch:
- (1) SPST 0.4A @24V
