Quick Summary
The HTW-WF81-963S is designed for indoor fan coil unit systems with water heating support. It controls a three-speed fan, one UFH output, and one heating or cooling valve. The unit supports four-pipe systems using simple on/off control logic. Modbus and WiFi allow both local control and system integration.
This Water Heating Thermostat is used in projects that combine floor heating and fan coil control. The page explains key functions, control logic, and main parameters in a clear way. It also helps users match the thermostat with system needs. Common questions and custom options are included for reference.
Key Features
These functions support stable operation in systems that combine water heating and fan coil units.
(01) Modbus communication
Modbus allows connection to BMS systems for central monitoring. It supports data exchange between devices. This Water Heating Thermostat helps improve system control and management.
(02) 3-speed fan and multi-output control
Three fan speeds allow simple airflow adjustment. Separate outputs control UFH and heating or cooling valves. This matches combined system layouts.
(03) Programmable scheduling
Weekly scheduling allows automatic temperature control during different periods. This helps reduce energy use when rooms are empty. It also keeps indoor comfort stable.
(04) Water heating control
The unit supports underfloor heating together with FCU operation. This Water Heating Thermostat manages mixed systems in one device. It improves flexibility in real projects. (If you don’t need water heating, click here)
(05) WiFi connection
WiFi allows remote access through a mobile app. This Water Heating Thermostat supports flexible daily use. It improves convenience and user experience.
Product Design and Display
The design is simple and clean for indoor installation. The screen is clear and easy to read. It fits standard wall boxes and common installation conditions.
Technical Specifications
The table below shows key parameters for system selection and operation.
| Parameter | Value |
|---|---|
| Power Supply | 95–240Vac, 50/60Hz |
| Power Consumption | WiFi 3W Max |
| Temperature Range | 5–95°C (41–203°F) |
| Floor Limit | 20–90°C (68–194°F) |
| Control Deviation | 0.5–10°C (Factory +1°C) |
| Ambient Temperature | -5–50°C |
| Protection Level | IP20 |
| Warranty | 2 Years |
Wiring Diagram
The diagram shows typical wiring for a combined system. It includes fan coil and floor heating control outputs.
Model Code Guide
The table below helps explain model options and system configuration.
| Model | Application |
| 743 | Timer + 2-pipe system |
| 853 | Timer + 2-pipe + limit sensor + room card + WiFi |
| 863 | Timer + 4-pipe + limit sensor + room card + WiFi |
| 963 | Floor heating & FCU + timer + limit sensor + room card + WiFi |
| S | RS485 Modbus |
| Example HTW-WF81-FC-xxx | If xxx=963S, it means 3 fan speed, 4-pipe system, water heating ,Wifi+ Modbus |
Project Fit & Customization
This model is not suitable for systems that need modulating valve control. It does not support advanced PID logic. It may also not fit projects requiring complex control strategies.
Despite these limits, some functions can be adjusted. Communication settings and control logic can be modified. Sensor inputs and system options can also be discussed.
OEM support is available for branding and design updates. Logo printing, colour changes, and labels can be customised. Packaging and interface layout can also be adjusted.
Certifications and Compliance
The thermostat meets common European standards and test requirements.
Exhibition Moments
Our team participates in international HVAC exhibitions and industry events.
Frequently Asked Questions
Q1: Can this thermostat control both FCU and floor heating?
Yes, it supports both fan coil and underfloor heating systems. It can manage combined systems. Please confirm wiring before installation.
Q2: Does it support BMS integration?
Yes, it supports Modbus communication. This allows connection to building systems. The Water Heating Thermostat supports central monitoring.
Q3: Can it work without WiFi?
Yes, it can operate without WiFi. Modbus can be used for control. WiFi is optional depending on the project.
Q4: Is it suitable for residential use?
Yes, it is designed for homes and light commercial spaces. It fits common indoor environments. Installation is simple.
Q5: What is the MOQ and can I get samples?
We support samples for testing. Standard MOQ is 300 units. Smaller quantities like 100 units can be discussed.
Q6: How to place an order and arrange shipping?
Contact us to confirm requirements and receive a PI. Payment supports TT, PayPal, and Visa. Shipping terms include EXW, FOB, and DAP.
Q7: How long does production take?
Non-custom samples ship within 7 days. Custom orders take about 3–5 weeks. Bulk orders around 300 units need about one month.
Q8: What shipping methods are available?
Express delivery takes about 7 days. Air freight is similar. Sea freight takes about one month depending on route.
Need Support?
If you are planning a project or selecting a model, please contact us. We can help review your system and suggest suitable options.
Related Thermostat Models
This section lists related thermostat models for different system types and integration needs, helping you choose a suitable option for your project.
In HVAC projects, stable control and simple operation are important. This Water Heating Thermostat manages fan coil and floor heating in one device. It helps improve system efficiency and supports comfortable indoor environments. Learned more modbus thermostat
