The Belimo ZONE325S-80 is a forged brass, 3-way on/off diverting zone valve with 1" sweat ends: Cv 8, 20 psi close-off, 300 psi body pressure rating and ANSI Class III 0.1% leakage, for chilled or hot water up to 50% glycol. It takes a ZONE spring return actuator, sold separately.
Typically used on 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. The compact body and actuator fit tight spaces where on/off control is needed.
Specifications per Belimo ZONE325S-80 technical data sheet 2023-01-10; ZONE325S-80 valve page of the ZONE325S-80 assembly data sheets 2022-01-12 (pipe connection). Reviewed 2026-10-09.
Best For
- Fan coil units, baseboards and other hydronic terminal units
- On/off diverting duty in hydronic systems with variable or constant flow
- Soldered piping with 1" sweat ends
- Pairing with a Belimo ZONE spring return actuator chosen for the control voltage
Warranty
Belimo covers the ZONE325S-80 valve with a 2-year warranty.
Key Features
3-way on/off diverting
Flow pattern 3-way, on/off diverting flow characteristic, ANSI Class III 0.1% leakage, Cv 8.
20 psi close-off
Close-off pressure 20 psi with a 300 psi body pressure rating.
Forged brass body
Forged brass valve body, EPDM seat and housing seal, stainless steel stem.
1" Sweat connection
1" sweat ends.
Water and glycol
Chilled or hot water up to 50% glycol, fluid temperature 32...212°F [0...100°C].
ZONE spring actuators
Belimo lists ZONE spring return actuators as suitable for this valve.
ZOT Supply is an authorized distributor of Belimo products.
Technical Specifications
Valve: Belimo ZONE325S-80
| Valve model | Belimo ZONE325S-80 |
| Valve size | 1 in. [DN 25] |
| Flow pattern | 3-way |
| Flow characteristic | on/off, diverting |
| Cv | 8 |
| Close-off pressure | 20 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 | sweat |
| Valve body | forged brass |
| Housing seal | EPDM |
| Stem | stainless steel |
| Seat | EPDM |
| Suitable actuators | ZONE (spring) |
| Dimensions A / B / C / D / E / F | 4.0 in. [102 mm] / 3.4 in. [86 mm] / 3.7 in. [93 mm] / 5.5 in. [140 mm] / 1.2 in. [30 mm] / 1.2 in. [31 mm] |
| Weight | 1.1 lb [0.50 kg] |
Documentation
FAQ
What is the Cv and close-off pressure of the Belimo ZONE325S-80?
Cv 8 with a 20 psi close-off pressure and a 300 psi body pressure rating.
Is the ZONE325S-80 a 2-way or 3-way valve?
3-way. The flow characteristic is on/off, diverting, with ANSI Class III 0.1% leakage.
Which actuators fit the Belimo ZONE325S-80?
Belimo lists ZONE spring return actuators as suitable for this valve. The actuator is sold separately.
What pipe connection does the ZONE325S-80 have?
1" sweat ends.
What fluids can the ZONE325S-80 control?
Chilled or hot water, up to 50% glycol, at fluid temperatures of 32...212°F [0...100°C].
- Valve Pattern:
- 3-Way
- Valve Size:
- 1 Inch
- Connection Type:
- Sweat
- CV Rating:
- 8.0
- Max Close-Off Pressure:
- 20 psi
- Max Operating Pressure:
- 300 psi
- Medium Temperature Range:
- 32-212 °F
- Body Material:
- Forged Brass
- Actuator Type:
- Valve Only
