Quick Summary
HTW-FT03-4EW is a WiFi Thermostat With External sensor designed for indoor fan coil unit (FCU) temperature control. It supports 4-pipe fan coil systems and manages the operation of the fan and two wired motorised valves for heating and cooling. The controller monitors temperature using either the internal sensor or an external probe and adjusts fan speed and valve operation to maintain a stable room environment. WiFi communication allows remote temperature monitoring and adjustment when required.
This page explains how the WiFi Thermostat With External sensor functions in a fan coil system, including its control logic and installation reference. You will also find wiring guidance, key technical specifications, model code explanation, project use considerations, and typical questions from installers and project buyers.
Key Functional Highlights
(This section explains the core control functions and their practical value.)
(01) 4-Pipe Fan Coil System Control
This WiFi Thermostat With External sensor supports 4-pipe FCU systems where heating and cooling are controlled independently. It operates the fan and two motorised valves, ensuring accurate switching between heating and cooling modes in mixed seasonal conditions. If you are interested in standalone model, please refer to this link: HTW-FT03-4.
(02) Remote Monitoring Through WiFi Communication
WiFi communication allows the thermostat to be monitored and adjusted remotely through a mobile network. This function helps property managers supervise temperature settings across multiple rooms and simplifies maintenance for distributed fan coil installations.
(03) External Sensor Temperature Measurement
The WiFi Thermostat With External sensor can work with an external temperature probe when more accurate sensing is required. This is useful when the thermostat position does not reflect the true room temperature, such as in concealed installation areas.
(04) Fan Speed and Valve Coordination
The controller manages three fan speeds and the opening of heating and cooling valves together. Coordinating these outputs helps the fan coil unit respond smoothly to temperature changes and improves the stability of the indoor climate.
Display
(This section shows the product’s dimensions and the interface layout.)
The HTW-FT03 thermostat is designed for wall installation and provides a clear temperature display for daily operation. The interface allows users to view room temperature, adjust the setpoint, and select fan speed or operating mode.
The front panel layout shows the display area and touch buttons, while the rear view indicates terminal positions and installation structure. Dimension drawings help installers confirm compatibility with EU or standard electrical wall boxes before installation.
Product angles (front / side / back in one image)
Dimensions and display layout
Specifications
(This section lists the key parameters for reference and project confirmation.)
| Parameter | Value |
|---|---|
| Power Supply | 95–240Vac |
| 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 |
| Protection Class | IP20 |
Wiring
(This section provides the wiring reference diagram for correct installation.)
The wiring diagram shows how the WiFi Thermostat With External sensor connects to the fan coil unit, fan speeds, and motorised heating and cooling valves.
Installers should follow the terminal layout carefully to ensure the fan relay and valve relays are connected correctly. Proper wiring ensures reliable fan operation and accurate temperature control in the FCU system.
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-WF11-FC-xx: if xx = 2EN, it stands for a 3-speed fan, 2-pipe system with on/off valve control, external sensor function, 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 WiFi Thermostat With External sensor is designed mainly for standalone fan coil temperature control in residential rooms, hotels, apartments, and small commercial buildings. It is suitable for projects where local temperature control is required without complex building automation integration. However, it may not be suitable for projects requiring full BMS integration with protocols such as BACnet or Modbus unless the corresponding communication model is selected.
Despite these limits mentioned above, functional adjustments can be discussed for certain projects. For example, temperature control logic, communication options, or sensor configuration may be adapted for specific installations. Such ODM-level function customisation usually depends on project scale and technical feasibility.
OEM customisation is also available for project partners. Options include logo printing on the thermostat panel, colour customisation such as black or white housing, packaging adjustments, and customised product labels for distribution projects.
Certifications
Exhibition Moments
Frequently Asked Questions
Q1. Can this WiFi thermostat be used with all fan coil units?
It works with most standard fan coil units using 3-speed fans and on/off motorised valves. Always confirm wiring compatibility with the FCU before installation.
Q2. When should an external temperature sensor be used?
An external sensor is recommended when the thermostat position cannot represent the actual room temperature, such as behind curtains or inside equipment cabinets.
Q3. Can the WiFi Thermostat With External sensor control heating and cooling automatically?
Yes. In a 4-pipe fan coil system, the thermostat controls both heating and cooling valves and switches operation according to the room temperature demand.
Q4. What is the minimum order quantity and are samples available?
Samples of the thermostat are available. Standard MOQ is around 300 units, but smaller trial quantities may be discussed depending on the project.
Q5. How can I place an order?
Please contact us to confirm your requirements. After confirmation, we will issue a proforma invoice. Payment methods include TT, PayPal, Visa and more.
Q6. How will the thermostats be shipped?
Courier door-to-door delivery usually takes about 7 days. Air freight also takes around one week, while sea freight normally requires one month or more.
Need Project Support?
If you are selecting a WiFi Thermostat With External sensor for a fan coil project, feel free to contact us. Our team can help confirm compatibility, wiring details, and suitable model options.
