The Belimo ZONE220N-35+ZONE120NO-S is a 3/4 in. (DN 20) 2-way on/off zone valve assembly: a ZONE220N-35 forged brass valve with NPT female ends, Cv 3.5 and 30 psi close-off, paired with a ZONE120NO-S AC 120 V normally open spring return actuator for fail-safe operation on 2-wire control. The -S actuator adds one built-in SPST auxiliary switch rated 5 A resistive (5 A inductive) at AC 120 V.
Best For
- Fan coil units
- Baseboard heating
- Other hydronic zone applications where fail-safe operation on 2-wire control is required
- Hydronic systems with variable or constant flow
- Compact installations that need on/off zone control
- On/off control from a thermostat or controller switching AC 120 V
Warranty
Belimo 2-year warranty on the ZONE220N-35+ZONE120NO-S.
Key Features
Spring Return Fail-Safe
Normally Open spring return actuator for fail-safe operation on 2-wire on/off control.
Forged Brass Body
Forged brass body, EPDM seat and housing seal, and stainless steel stem. 300 psi body pressure rating.
Cv 3.5, 30 psi Close-Off
On/off flow characteristic, Cv 3.5, 30 psi close-off pressure and ANSI Class III 0.1% leakage.
NPT Female Connections
3/4 in. (DN 20) NPT female ends for chilled or hot water, up to 50% glycol, at 32...212°F [0...100°C].
Built-In Auxiliary Switch
One built-in 1 x SPST auxiliary switch rated 5 A resistive (5 A inductive) @ AC 120 V, wired on red leads to the auxiliary circuit.
cULus and CE Listed
CE, cULus listed actuator, manufactured under ISO 9001, NEMA 1 / UL Enclosure Type 1, maintenance-free.
ZOT Supply is an authorized distributor of Belimo products.
Technical Specifications
| Valve: ZONE220N-35 | |
| Valve Size | 3/4 in. (0.75 in.), DN 20 |
|---|---|
| Flow Pattern | 2-way |
| Flow Characteristic | on/off |
| Cv | 3.5 |
| Close-Off Pressure | 30 psi |
| Body Pressure Rating | 300 psi |
| Leakage Rate | ANSI Class III 0.1% |
| Fluid | chilled or hot water, up to 50% glycol |
| Fluid Temperature Range (Water) | 32...212°F [0...100°C] |
| Pipe Connection | NPT female |
| Valve Body | forged brass |
| Housing Seal | EPDM |
| Stem | stainless steel |
| Seat | EPDM |
| Suitable Actuators | Belimo ZONE spring return |
| Actuator: ZONE120NO-S | |
| Nominal Voltage | AC 120 V |
| Nominal Voltage Frequency | 50/60 Hz |
| Power Consumption in Operation | 6.5 W |
| Transformer Sizing | 7 VA |
| Control | On/off, 2-wire |
| Normal Position | Normally Open (NO) |
| 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...104°F [0...40°C] |
| Storage Temperature | -40...176°F [-40...80°C] |
| Ambient Humidity | Max. 95% RH, non-condensing |
| Servicing | maintenance-free |
| Housing Material | galvanized steel |
Specifications sourced from the Belimo ZONE220N-35+ZONE120NO-S technical data sheet (2022-01-12 edition). Reviewed October 10, 2026.
Documentation
Technical Data Sheet: Belimo ZONE220N-35+ZONE120NO-SInstallation Instructions: ZONE Series Zone ValvesFAQ
What is the Cv of the Belimo ZONE220N-35+ZONE120NO-S?
The ZONE220N-35 valve in the Belimo ZONE220N-35+ZONE120NO-S has a Cv of 3.5 and a close-off pressure of 30 psi. It is a 3/4 in. 2-way valve with an on/off flow characteristic.
What pipe connection does the Belimo ZONE220N-35+ZONE120NO-S have?
The Belimo ZONE220N-35+ZONE120NO-S has 3/4 in. NPT female pipe connections on a forged brass valve body.
What fluids and temperatures can the Belimo ZONE220N-35+ZONE120NO-S handle?
It is rated for chilled or hot water, up to 50% glycol, with a fluid temperature range of 32...212°F [0...100°C] and a 300 psi body pressure rating.
What voltage does the ZONE120NO-S actuator on the Belimo ZONE220N-35+ZONE120NO-S use?
The ZONE120NO-S runs on AC 120 V, 50/60 Hz. It draws 6.5 W in operation; size the transformer at 7 VA.
Is the Belimo ZONE220N-35+ZONE120NO-S normally open or normally closed?
The Belimo ZONE220N-35+ZONE120NO-S uses the ZONE120NO-S, the normally open (NO) version of the Belimo ZONE spring return actuator, for on/off control on 2 wires.
Does the Belimo ZONE220N-35+ZONE120NO-S have an auxiliary switch?
Yes. The ZONE120NO-S has one built-in 1 x SPST auxiliary switch rated 5 A resistive (5 A inductive) @ AC 120 V, wired on red leads.
What wiring connection does the ZONE120NO-S have?
The ZONE120NO-S has 6 in. wire leads.
What is the warranty on the Belimo ZONE220N-35+ZONE120NO-S?
Belimo covers the ZONE220N-35+ZONE120NO-S with a 2-year warranty.
- Valve Pattern:
- 2-Way
- Valve Size:
- 3/4 Inch
- Connection Type:
- NPT
- CV Rating:
- 3.5
- Actuator Type:
- Fail-Safe
- Voltage:
- 120VAC
- Control Signal:
- On/Off
- Auxillary Switch:
- (1) SPST 5A @120V
