Three-way mixing valve Termojet, DN50, kvs-40 female thread

Termojet DN50 three-way rotary mixing valve — the largest size in the line with internal thread Rp 2" and flow coefficient Kvs 40 m³/h. Working pressure PN 10 bar, temperature range –10…+110°C. Body made of CW617N brass, EPDM seals. The valve is designed for automatic mixing of heat transfer fluid in large heating systems and is installed with an actuator with 3-point or proportional 0–10V control.

Technical Specifications

Operating Principle

Three valve ports: A — hot supply from boiler or heat station, B — return heat transfer fluid from the system, AB — mixed flow outlet to the distribution manifold. The disc rotates from 0° to 90° on actuator command — continuously varying the ratio of hot and return fluid. The linear flow characteristic Kvs 40 ensures stable control even under sharp load changes. EPDM seals withstand prolonged operation with heat transfer fluids containing up to 50% glycol.

Applications

• Industrial and commercial boiler rooms (from 120 kW). DN50 Kvs 40 — for systems with high heat transfer fluid flow rates: production facilities, shopping centres, multi-apartment buildings with a central heat station.
• Heat stations and metering units. The DN50 valve is installed on the supply pipeline after the heat exchanger to regulate temperature in the consumer network.
• Weather-compensated control of large boiler rooms. Paired with the Termojet 411 (0–10V) actuator and a weather-compensated controller, the valve automatically adjusts supply temperature based on outdoor temperature — significant fuel savings at large facilities.
• Balancing between multiple circuits. A single DN50 valve can provide a mixed flow for several sub-circuits with smaller DN — radiator branches, underfloor heating circuits, ventilation heating coils.
• Systems with a backup heat source. The DN50 valve ensures the required flow volume when switching between the primary and backup boiler or heat pump.

Advantages of Termojet DN50

• CW617N brass body — precision and durability meeting quality standards for industrial applications.
• Kvs 40 m³/h — the highest value in the range, covering the needs of systems rated 120 kW and above.
• Leakage below 0.1% — minimal heat losses in the closed disc position.
• EPDM seals — resistance to glycol-based heat transfer fluids and temperatures up to 110°C.
• Standard mounting — installation of 405N/411 series actuators without adapters.

Compatible Actuators

For the Termojet DN50 Kvs 40 valve (disc torque below 5 Nm), actuators with a torque of 6 Nm are recommended:

• Termojet 405N electric actuator (3-point, 230V) — for boiler rooms with a 3-position controller, smooth control of large industrial systems.
• Termojet 411 electric actuator (0–10V, 24V) — for proportional control with a weather-compensated controller or SCADA system.

Valve and Heat Pump

For large bivalent systems — heat pump as the base source and boiler in peak mode — the DN50 valve ensures the required flow volume with both sources operating. Paired with the 411 (0–10V) actuator, it integrates into the heat pump control system via a 0–10V analogue output, providing smooth proportional control without water hammer. More about solutions for large systems — on the Termojet heat pumps website.

Frequently Asked Questions

What system capacity is DN50 suitable for?
Kvs 40 and DN50 are designed for systems approximately from 120 kW. Precise selection — using the formula Kvs ≥ Q / √ΔP, where Q is the heat transfer fluid flow rate in m³/h, ΔP is the calculated pressure drop across the valve (typically 0.3–0.5 bar). For smaller systems, DN40 (Kvs 25) or DN32 (Kvs 16–18) is sufficient.

What is Rp thread type and how does it differ from G?
Rp is a parallel pipe thread with sealing at the face of the fitting (via gasket or sealant). G is a tapered thread with sealing on the threads. The DN50 valve has Rp 2" (internal parallel) — connect the appropriate union or fitting with a flat face.