3 F820 34
The RELIO smart wireless room thermostat enables modern management of heating and cooling systems through local control and remote monitoring via the ENGO Smart mobile application. The system comprises a wall-mounted/portable unit and a relay receiver communicating via a stable 868 MHz RF connection. Featuring built-in Wi-Fi connectivity, customizable weekly schedules, and TPI control, it offers seamless heating customization and noticeable energy savings. Reliable operation is complemented by frost protection features, PIN-code keypad locking, and a high-capacity 16 A relay output for controlling a wide variety of loads.
| ITEM CODE | EAN | CONNECTIVITY | POWER SUPPLY | L | H | L1 |
| 3 F820 34 | 3838963250586 | WiFi, 2.4GHz |
Thermostat: 2 x AA batteries (2 x 1.5 V) Receiver: 230 VAC, 50 Hz |
80 96 |
80 96 |
22 27 |
The RELIO smart Wi-Fi room thermostat is a modern, advanced solution for precise wireless management of heating or cooling systems in residential, commercial, or industrial buildings. The thermostat offers comprehensive control both locally (via intuitive on-device buttons) and remotely via the HERZ Thermiq mobile application.
Key features:
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Universal control of heating and cooling appliances: Suitable for direct control of gas, oil, or pellet boilers, heat pumps, circulation pumps, electro-thermal actuators, and underfloor heating wiring centres.
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Dual wireless connectivity:
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868 MHz radio frequency link: Stable and reliable wireless communication between the wall thermostat (transmitter) and receiver, offering a range that easily overcomes building obstacles.
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2.4 GHz Wi-Fi connection: Enables direct connection to your home network, providing complete temperature control anywhere, anytime via smartphone or tablet.
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Flexible scheduling and timers: The HERZ Thermiq app allows you to easily create daily and weekly heating/cooling schedules tailored to your lifestyle.
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Precise regulation and algorithms: Choose between an advanced TPI algorithm (which learns and utilizes cyclical switching to eliminate temperature swings and reduce energy consumption) and traditional hysteresis (adjustable from 0.1 °C to 2.0 °C).
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Safety and energy-saving functions:
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Frost protection (Anti-Frost): Automatically initiates heating if the ambient temperature drops below a safe threshold.
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Child lock / PIN protection: Lock the thermostat's buttons to prevent unauthorized tampering with settings.
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Minimum and maximum temperature limits: Set upper and lower boundaries for the target temperature for enhanced energy consumption control.
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Device sharing: Easily share thermostat access with multiple family members or users directly through the app.

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EC Compliance
By affixing the CE mark, the manufacturer declares that HERZ Thermiq complies with the following relevant safety regulations:
• EU Low Voltage Directive 2014/35/EU
• EU Electromagnetic Compatibility Directive 2014/30/EU
• EU RoHS Directive 2011/65/EU
• EU WEEE Directive 2012/19/EU (Reg. No. DE 23479719)
Compliance has been verified, and the corresponding documentation and EU Declaration of Conformity are kept by the manufacturer.
| Parameter | Value |
| Thermostat power supply | 2 x AA battery (3 VDC) |
| Receiver power supply | 230 VAC, 50 Hz |
| Maximum total load | 16 A |
| Temperature setting range | 5°C - 45°C |
| Temperature display accuracy | 0.1°C |
| Hysteresis | from +/-0.1 to +/- 2°C |
| Communication | wireless (WiFi or FM 868MHz) |
| Outputs | Volt-free contact (NO/COM) |
| Protection rating | IP30 |
| Dimensions [mm] | 80 x 80 x 22 |
| Dimensions [mm] | 96 x 96 x 27 |
Installation guidelines:
Mount the thermostat (transmitter) on an internal room wall at a height of approximately 1.5 m from floor level. The installation location should be shielded from direct sunlight, draughts, air conditioners, and other sources of heat or cold.
Thermostat mounting options:
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Wall flush-mounted or surface-mounted installation: Securing the rear housing to the wall or a standard flush-mounting junction box.
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Free-standing use (portable thermostat): Using the included table stand, the thermostat can be placed on a table, sideboard, or nightstand in any room.

Receiver wiring (wiring diagrams):
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Connection to a boiler or heat pump: The volt-free NO / COM contact of the receiver connects to the control terminals (ON/OFF) of the heat source.
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Direct 230 V control (pump / actuator / electric heating appliance): The volt-free contact switches the phase conductor (230 V AC) to the load up to a maximum of 16 A.

- Flyer - ENG
- Data sheet - ENG
- Installation manual
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