Quick Summary
The HTW-WF02-FC-4N Modbus Thermostat for 4 Pipe is designed for fan coil systems with independent heating and cooling circuits. It controls a 3-speed fan and two on/off motorised valves for heat and cool operation. The thermostat supports RS485 Modbus communication, allowing integration into building management systems for central monitoring and control.
This page explains how the Modbus Thermostat for 4 Pipe operates in FCU systems and why its control logic suits multi-room projects. It also includes wiring reference, key parameters, and model selection guidance, followed by project considerations, customisation options, and common questions with clear answers.
Key Features
(This section explains the core control functions and their practical value.)
(01) 4-pipe system control
The Modbus Thermostat for 4 Pipe supports independent heating and cooling circuits. This allows better temperature stability and avoids seasonal switching, making it suitable for hotels and office environments. We have another model HTW-WF02-FC-2N designs for 2 pipe system.
(02) Modbus RS485 communication
The Modbus Thermostat for 4 Pipe supports RS485 Modbus integration. It allows central monitoring and unified control logic across rooms, improving system management and operational efficiency.
(03) 3-speed fan control
Three fan speeds provide flexible airflow adjustment. This helps maintain stable comfort while balancing noise and performance in daily operation across different room conditions.
(04) On/off valve control
The thermostat controls two on/off motorised valves for heating and cooling. This aligns with common FCU design and ensures simple and reliable system operation.
Product Design and Display
(This section shows the product’s dimensions and the interface layout.)


Technical Specifications
(This section lists the key parameters for reference and project confirmation.)
| Power Supply | 100~250Vac |
| Frequency | 50/60Hz |
| Fan Relay Load | 5A (3A inductive) |
| Valve Relay Load | 3A (1A inductive) |
| Accuracy | ±0.5°C or ±1°F |
| Sensor | NTC3950, 10K |
| Setpoint Range | 5~35°C |
| Installation | EU or standard electric box |
Wiring Diagram
(This section provides the wiring reference diagram for correct installation.)

Model Code Guide
(This section explains what configuration the model code refers to.)
| Fan coil series | xx stands for |
| EC | EC fan |
| 2/4 | 2 for 2-pipe on/off; 4 for 4-pipe on/off system |
| M | Modulating valve control |
| W | Wi-Fi |
| N/B | N for Modbus; B for BACnet |
| K/E | K for Keycard; E for External sensor |
| Example | HTW-WF02-FC-xx: if xx = 4N, it stands for a 4-pipe system with on/off valve control and Modbus communication. Most sub-models are ready-made. Kindly contact us to confirm availability. |
Project Fit & Customization
(This section explains where the product can be used, its limits, and OEM/ODM options.)
The Modbus Thermostat for 4 Pipe is suitable for FCU systems requiring central control through BMS. It is not suitable for standalone-only projects or systems requiring WiFi or BACnet communication.
Despite these limits mentioned above, ODM customisation can be discussed based on project requirements. Communication protocols or control logic may be adjusted where feasible, depending on system compatibility and project scale.
OEM customisation is also supported. Options include logo printing, colour customisation, and label design. These help align the product with project branding and installation needs.
Certificates and Compliance


Frequently Asked Questions
Q1. Can this thermostat be used in 2-pipe systems?
No, this model is designed for 4-pipe systems with independent heating and cooling control.
Q2. Does it support building management system integration?
Yes, the Modbus Thermostat for 4 Pipe supports RS485 Modbus for central monitoring and control.
Q3. Is it suitable for hotel or office projects?
Yes, it is suitable where central control and stable temperature management are required across multiple rooms.
Q4. Do you support samples and what is the MOQ?
Yes, samples are available. MOQ is usually 300 units, but smaller quantities can be discussed.
Q5. How can we place an order?
Please contact us to confirm requirements. We will issue a PI. Payment supports TT, PayPal, Visa. Terms include EXW, FOB, DAP.
Q6. How will the goods be shipped?
Courier delivery takes about 7 days. Air freight is similar. Sea shipping usually takes over one month depending on destination.
Related Thermostat Models
For standalone 4-pipe applications, you may refer to /products/htw-wf02-fc-4, or contact us for project selection support.
The Modbus Thermostat for 4 Pipe suits FCU systems requiring central control and stable operation. It supports consistent room management. It helps improve efficiency in multi-room projects. 【More models: fan coil thermostat】

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