Quick Summary
The HTW-WF03-FC-4 Smart Room Thermostat is designed for 4-pipe fan coil systems with independent heating and cooling circuits. It controls a 3-speed fan and two motorised valves for heat and cool operation. The control logic allows stable switching and precise temperature regulation, making it suitable for modern FCU installations.
This page explains how the Smart Room Thermostat works in 4-pipe systems and why it supports flexible room control. It also includes wiring reference, technical parameters, and model guidance, followed by project considerations, customisation options, and practical questions with clear answers.
Key Features
(This section explains the core control functions and their practical value.)
(01) 4-pipe system control
The Smart Room Thermostat supports separate heating and cooling circuits. This improves temperature stability and allows flexible operation without seasonal system switching. If you need the thermostst for 2-pipe system, please refer to this link: HTW-WF03-FC-2.
(02) Independent valve control
The Smart Room Thermostat controls two motorised valves for heating and cooling. This ensures accurate control and reliable performance in complex FCU systems.
(03) 3-speed fan operation
Three fan speeds allow flexible airflow adjustment. This helps maintain stable indoor comfort while balancing noise and system efficiency.
(04) Simple and stable operation
The Smart Room Thermostat uses straightforward control logic. This supports reliable performance and easy operation in daily use across different room environments.
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-WF03-FC-xx: if xx = 4, it stands for a 4-pipe system with on/off valve control. 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 Smart Room Thermostat is suitable for FCU systems requiring independent heating and cooling control. It is not suitable for projects needing Modbus, BACnet, or central BMS integration.
Despite these limits mentioned above, ODM customisation can be discussed based on project needs. Control functions or interface design may be adjusted where feasible depending on system compatibility.
OEM customisation is also supported. Options include logo printing, colour customisation, and label design. These help align the thermostat with project branding and installation requirements.
Certificates and Compliance


Frequently Asked Questions
Q1. Can this thermostat be used in 2-pipe systems?
No, this model is designed specifically for 4-pipe systems with separate heating and cooling control.
Q2. Does it support BMS integration?
No, this is a standalone Smart Room Thermostat without Modbus or BACnet communication.
Q3. What valves does it control?
It controls two on/off motorised valves for heating and cooling in 4-pipe FCU systems.
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 2-pipe systems, you may refer to /products/htw-wf03-fc-2, or contact us for project selection support. You can refer to below links:
The Smart Room Thermostat suits 4-pipe FCU systems requiring flexible control. It supports stable operation. It helps improve comfort and system performance. 【More models: fan coil thermostat】
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