ZONE225N-80+ZONE120NO-S Overview
The Belimo ZONE225N-80+ZONE120NO-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 ZONE120NO-S AC 120 V normally open 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 open position. The actuator runs on AC 120 V, 50/60 Hz, draws 6.5 W in operation and connects with 6 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
- AC 120 V line-voltage control circuits
- Projects that need a built-in auxiliary switch for an auxiliary circuit
Warranty
The Belimo ZONE225N-80+ZONE120NO-S carries a 2-year Belimo warranty.
Key Features
Fail-Safe Spring Return
The ZONE120NO-S actuator is normally open: when power is removed, the spring returns the valve open.
Simple On/Off Control
AC 120 V, 50/60 Hz on/off control with 6.5 W in operation, 90° rotation and 6 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.
Quiet Operation
Motor and fail-safe noise levels of 35 dB(A).
Built-In Auxiliary Switch
1 x SPST, 5 A resistive (5 A inductive) @ AC 120 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 (ZONE120NO-S) | |
| Actuator model | ZONE120NO-S |
| Actuator type | Spring return, on/off |
| Normal position | Normally Open (NO) |
| Nominal voltage | AC 120 V |
| Nominal voltage frequency | 50/60 Hz |
| Power consumption in operation | 6.5 W |
| Transformer sizing | 7 VA |
| Auxiliary switch | 1 x SPST, 5 A resistive (5 A inductive) @ AC 120 V |
| Electrical connection | 6 in. wire leads |
| Angle of rotation | 90° |
| Noise level, motor | 35 dB(A) |
| Noise level, fail-safe | 35 dB(A) |
| 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+ZONE120NO-S?
The ZONE225N-80+ZONE120NO-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+ZONE120NO-S when power is lost?
The ZONE120NO-S is a normally open spring return actuator. When power is removed, the spring returns the valve to its open position.
What power supply does the ZONE120NO-S actuator need?
AC 120 V, 50/60 Hz. It draws 6.5 W in operation, is sized at 7 VA for transformer selection and connects with 6 in. wire leads.
What is the auxiliary switch rating on the Belimo ZONE225N-80+ZONE120NO-S?
One built-in SPST auxiliary switch rated 5 A resistive (5 A inductive) @ AC 120 V, wired on two red leads to the auxiliary circuit.
Does a normally open zone valve like the ZONE225N-80+ZONE120NO-S need attention in the heating off season?
Yes. For heating applications, cycle normally open valves periodically during the off season or power them down to reduce the chance of the valve sticking in the coming heating season.
How should the Belimo ZONE225N-80+ZONE120NO-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+ZONE120NO-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:
- 120VAC
- Control Signal:
- On/Off
- Auxillary Switch:
- (1) SPST 5A @120V
