Three-way mixing valve Termojet, DN25, kvs-6 male thread

The Termojet DN25 three-way rotary mixing valve is a fitting with a rotary plug and external thread G 1" for automatic mixing of the heating medium in heating systems. Flow coefficient Kvs 6 m³/h, working pressure PN 10 bar, operating temperature range –10…+110°C. The valve is designed for use with an actuator and allows smooth adjustment of the supply temperature to the circuit — from fully hot to fully return.

Technical Specifications

Operating Principle

The valve has three ports: A — hot heating medium supply from the boiler, B — return from the heating circuit, AB — outlet to the circuit. When the plug rotates 90° following the actuator signal, the ratio of hot and return flows changes smoothly — the temperature at outlet AB is regulated steplessly. The linear flow characteristic Kvs 6 ensures accurate dosing across a wide load range. EPDM seals guarantee leakage less than 0.1% Kvs.

Applications

• Underfloor heating. DN25, Kvs 6 — the optimal size for a mixing unit of a floor circuit with an area of 80–150 m²: maintains supply temperature of 35–45°C regardless of the boiler temperature.
• Mixed systems. One valve for the underfloor heating circuit in a house with radiators — separate control without installing separate circuits.
• Weather-compensated control. Combined with the 411 actuator (0–10V) and a weather-compensated controller, the valve smoothly reduces supply temperature depending on outdoor temperature.
• Boiler room with multiple circuits. DN25 covers standard residential capacities; for larger systems consider DN32–DN50.
• Manual balancing. Without an actuator, the valve can be locked in any position for static temperature setting.

Advantages of Termojet DN25

• Brass body CW617N — precision and durability on par with leading counterparts.
• Leakage less than 0.1% — minimal losses in the closed plug position.
• Standard actuator mount — installation of 401N/405N/411 series actuators without additional adapters.
• EPDM seals — resistance to heating media with glycol additives.
• A worthy replacement for imported mixing valves of equivalent DN and Kvs — without customs delays, with standard installation dimensions.

Compatible Actuators

For automation of the Termojet DN25 Kvs 6 valve, use actuators with a torque of at least 6 Nm (valve plug torque — less than 3 Nm, twice the reserve):

• Termojet 401N actuator (3-point, 230V) — for fast zoning and simple boiler controllers.
• Termojet 405N actuator (3-point, 230V) — smoother control, suitable for all DN.
• Termojet 411 actuator (0–10V, 24V) — for weather-compensated automation, smart home, integration with heat pump.

Valve and Heat Pump

Heat pumps operate most efficiently at low heating medium temperature. The DN25 Kvs 6 three-way mixing valve allows maintaining supply temperature to the floor circuit at 35–40°C even if the heat pump delivers 45°C. Combined with the 411 actuator (0–10V), the valve provides smooth weather-compensated control that improves the COP of the entire system. For integrated heat pump solutions — visit the Termojet heat pumps website.

Frequently Asked Questions

How to choose the Kvs for a three-way mixing valve?
Kvs 6 (DN25) covers underfloor heating circuits with an area of 80–150 m² or mixed systems of medium capacity. Approximate formula: Kvs ≥ Q / √ΔP, where Q — flow rate in m³/h, ΔP — pressure differential across the valve (typically 0.3–0.5 bar). For smaller circuits — consider DN20 Kvs 2.5. For larger systems or boiler rooms — DN32 and above.

Can the valve be installed without an actuator?
Yes. The valve handle can be locked in any position — for manual static temperature setting. For automatic weather-compensated or proportional control — install one of the compatible actuators from the 401N/405N/411 series.