Quick Summary
The HTW-WF02-FC-2N Modbus Thermostat is designed for 2-pipe fan coil systems with heating and cooling changeover. 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 works 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) 2-pipe system control
The Modbus Thermostat supports standard 2-pipe fan coil systems with heating and cooling changeover. This aligns with common HVAC design and helps maintain stable temperature control across typical installations. Another model HTW-WF02-FC-4N designes for 4 pipe system with Modbus function.
(02) Modbus RS485 communication
The Modbus Thermostat supports RS485 Modbus integration. It enables central monitoring and unified control logic across rooms, improving operation efficiency and simplifying system management.
(03) 3-speed fan control
Three fan speeds allow flexible airflow adjustment. This helps maintain consistent comfort while balancing noise and performance in daily operation across varying room loads.
(04) On/off valve control
The thermostat controls on/off motorised valves for heating and cooling. This matches standard FCU system layouts and ensures simple, stable, and reliable control behaviour.
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 = 2N, it stands for a 2-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 is suitable for FCU systems requiring central control through BMS in 2-pipe layouts. 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 4-pipe systems?
No, this model is designed for 2-pipe systems with heating and cooling changeover.
Q2. Does it support building management system integration?
Yes, the Modbus Thermostat 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 4-pipe Modbus applications, you may refer to /products/htw-wf02-fc-4n, or contact us for project selection support.
The Modbus Thermostat suits 2-pipe FCU systems requiring central control and stable operation. It supports consistent room management. It helps improve efficiency in multi-room projects.【More details: Fan coil thermostat】






