SunTouch 15 Amp Relay R4 Wi-Fi Dual Voltage Control - Relay

Our review of the SunTouch SunStat Relay R4 finds it best suited to homeowners and installers who need reliable, high-capacity control for electric floor heating systems. The bottom line: this relay is a practical solution when a system requires more than 15 amps and the installer wants simple integration with modern SunStat thermostats and the SunStat ConnectPlus wireless ecosystem. The built-in GFCI and status indicators provide visible safety confirmation, while the dual-voltage capability and daisy-chaining option scale well for larger zones.

Key Features

• Dual-voltage control: Handles both 120V and 240V systems so a single relay model fits a variety of electric floor heating installations.
• High-capacity coverage: Controls up to 150 sq. ft. at 120V or 300 sq. ft. at 240V and can be daisy-chained to manage up to 1,500 sq. ft. or 3,000 sq. ft. respectively.
• Wireless communication: Built-in 915MHz wireless lets the relay pair with the SunStat ConnectPlus Thermostat for Wi-Fi control via the Watts Home app and voice assistants.
• Direct thermostat wiring: Wires directly to SunStat Connect, Connect Plus, and Command thermostats for straightforward control of larger systems.
• Integrated safety features: Includes a built-in GFCI and status indicators to help ensure safe, reliable operation during installation and use.

Who It's For

The Relay R4 is aimed at homeowners, electricians, and HVAC professionals installing or upgrading SunTouch electric radiant floor heating for medium to large areas where loads exceed 15 amps. It is particularly useful when remote monitoring or voice control is desired via the SunStat ConnectPlus Thermostat and Watts Home app.

It is not intended for older SunStat thermostats or legacy relay models, so anyone maintaining an older installation should verify compatibility or choose a relay specifically for legacy equipment instead of this model.

Pros & Cons

Pros

• Supports both 120V and 240V systems, reducing the need for multiple relay types.
• Can daisy-chain up to ten relays for expansive coverage, making it ideal for large installations.
• Built-in GFCI and status indicators improve safety and troubleshooting during installation.
• Wireless 915MHz pairing with ConnectPlus enables app and voice control for convenience.

Cons

• Requires a dedicated additional 20-amp circuit and individual breaker per relay, which can increase installation cost and complexity.
• Not compatible with older model thermostats or relays, so legacy systems may need replacement components.

Specifications

Device type	Dual-voltage relay for electric floor heating
Voltage	120V / 240V
Coverage	Up to 150 sq. ft. at 120V, 300 sq. ft. at 240V
Daisy-chain capacity	Up to 10 relays (1,500 sq. ft. at 120V / 3,000 sq. ft. at 240V)
Safety features	Built-in GFCI and status indicators
Wireless	915MHz wireless compatible with SunStat ConnectPlus
Thermostat compatibility	Wires to SunStat Connect, Connect Plus, Command

Our Verdict

The SunTouch Relay R4 is a sensible choice for modern electric floor heating projects that need more than 15 amps of control and that will pair with current SunStat thermostats. Its combination of dual-voltage support, daisy-chaining for large areas, and wireless connectivity via the ConnectPlus ecosystem deliver flexible control and good long-term value for owners and contractors willing to add the required circuits and breakers.

Frequently Asked Questions

Can this relay be used with older SunStat thermostats?
The Relay R4 should not be used with older model thermostats or relays; it is designed for use with current SunStat Connect, Connect Plus, and Command thermostats.

How much area can one relay control?
One relay controls up to 150 sq. ft. at 120V or 300 sq. ft. at 240V, and up to ten relays can be daisy-chained for much larger coverage.

Does the relay support remote control and voice assistants?
Yes, when paired wirelessly with the SunStat ConnectPlus Thermostat it supports Wi-Fi control through the Watts Home app and works with Alexa and Hey Google for voice control.