The MENRED Big3.1 is an intelligent mixing pump station for hydronic heating and cooling distribution. It packs a variable-frequency circulation pump, a three-way proportional mixing valve, and full sensor feedback into one wall-mounted unit measuring 450 × 320 × 253 mm. The station controls water temperature to ±1 °C, moves up to 6 m³/h through DN40 connections, and draws no more than 200 W. One compact box does the work of a full mixing and pumping assembly.

The Big3.1 serves as the four-port mixing hub between the primary circuit and the terminal circuit. It fits air conditioning loops, radiant floor heating and cooling, and ceiling radiant systems, which makes it a core building block for villas, apartments, energy-efficient homes, and WUHENG climate comfort systems.

Large-Bore DN40 Hydraulics: 6 m³/h Flow, 11 m Head

Small pipes choke big systems. The Big3.1 avoids this with G1-1/2″ male connections (nominal DN40, four ports) and a maximum flow of 6 m³/h at up to 11 m of head. The large bore keeps flow resistance low across the whole distribution loop. One station can supply large radiant surfaces without strain, and the 10 bar maximum working pressure covers standard residential system demands.

Precise Mixing Control with ±1 °C Accuracy

A proportional actuator drives the three-way mixing valve through three positions: 0°, 45°, and 90°. A temperature sensor and a pressure sensor feed live data back to the control box. The station then holds the supply water temperature within ±1 °C of the setpoint, adjustable between 5 and 75 °C. Stable water temperature means stable room comfort. If power fails, the actuator can be adjusted by hand, and it detaches without tools for fast service.

Built-In Inverter Pump for Lower Energy Use

The circulation pump uses variable-frequency drive. It runs in constant-flow mode by default, which guarantees maximum head, or in constant-pressure mode with an automatically variable differential. Three fixed speed levels (1/2/3) are also available. The pump only works as hard as the system asks, so energy use stays low and control response stays sharp. Maximum power draw is just 200 W.

Three Control Modes, One Smart Station

The Big3.1 offers three ways to run, with a clear priority order of standalone first, system second, Bluetooth third:

• Bluetooth (default): connect a phone through the Guyu Bluetooth WeChat mini-program to set parameters and switch the station on or off.

• System mode: join the AIO.4G HVAC cloud platform for remote operation as part of a smart IoT system (the cloud platform is not included as standard).

• Standalone mode: link the station to other equipment through passive dry-contact signals, with no network needed.

Parallel Operation Without Downtime

Two Big3.1 stations can run in parallel on one system. If one unit needs service, the other keeps the loop running. Heating does not stop. Cooling does not stop. For homes that depend on continuous climate control, this redundancy is a real safeguard, not a spec-sheet line.

Core Technologies & Benefits

Six engineered components work together inside the Big3.1:

• Variable-Frequency Circulation Pump: cuts energy use and improves control response across changing loads.

• Three-Way Proportional Mixing Valve: blends primary and return water for precise supply temperature.

• Temperature Sensor & Pressure Sensor: continuous feedback keeps control accurate at ±1 °C.

• Control Box: one controller manages pump, valve, and communication (RS485).

• Bypass Valve: protects the pump and balances flow when terminal circuits close.

• IP56 Waterproof Anti-Scale Actuator + EPP Insulation: the actuator resists water and scale; the EPP shell insulates every pipe run inside the station and prevents condensation.

Installation & Safety

• Wall mounting: fix with M6 expansion bolts in φ10 mm holes at 276.5 mm spacing; check the unit is level.

• Multiple units: keep at least 50 mm between stations installed side by side for service access.

• Electrical safety: installation by qualified personnel only, with leakage protection on the supply.

• Pump protection: never run the pump dry.

• Operating limits: indoor use only, at altitudes up to 2,000 m.

Technical Specifications