ZigBee 3.0
Flush-Mounted 230V
COM/NO Relay Output — 3(1)A
Humidity Sensor Built-In
Alexa & Google
5-Year Warranty
The ENGO EONE-230B is a flush-mounted, mains-powered ZigBee 3.0 smart thermostat in matt black — designed for permanent wall installation in a standard 60 mm back box. Powered by 230V AC with a volt-free COM/NO relay output rated at 3(1)A, it wires directly to a wiring centre, zone valve, or UFH control box without a separate receiver. It includes a built-in humidity sensor, TPI algorithm, floor sensor input, hotel card input, and full app and voice control via the ENGO EGATE-PRO gateway. The black-finish, permanently installed smart thermostat for new-build, professional, and design-conscious UFH and boiler control.
The EONE-230B is the black, flush-mounted version of the ENGO ONE range — functionally identical to the EONE-230W but finished in matt black to complement dark interiors, brushed metal finishes, and premium switch plate sets. It installs in a standard 60 mm back box and sits just 13.5 mm proud of the wall — sharp, flat, and unobtrusive. For installers and designers specifying a consistent black-finish smart control system, the EONE-230B pairs naturally with the EONE-BATB, EGATE-PRO, and ENGO's other black-finish products.
Why Buy the ENGO EONE-230B?
🖤 Matt Black Flush-Mounted DesignA premium dark finish for modern interiors — pairs with brushed nickel, anthracite, and black switch plates. Matches EONE-BATB and other black ENGO products for a consistent look.
🔌 Mains-Powered — Always OnWired to 230V AC permanently — no battery management, no USB charging, no risk of the thermostat going offline from a flat battery.
⚡ Built-In COM/NO Relay Output3(1)A volt-free relay switches wiring centres, zone valves, and control box inputs directly — no separate receiver module needed in many standard installations.
📡 ZigBee 3.0 — Full Smart ControlRemote access, 7-day scheduling, temperature history, and voice control via the EGATE-PRO gateway and ENGO Smart app.
💧 Built-In Humidity SensorRoom relative humidity displayed on screen and logged in the app — useful for comfort monitoring and condensation risk assessment in bathrooms and kitchens.
🌐 ENGO Binding — Offline ReliabilityDirect ZigBee binding to ECB62-ZB or EMOD-ZB means heating keeps running without internet — essential for a primary heating controller.
🌡️ TPI or Hysteresis ControlTPI reduces overshoot for efficient, stable UFH temperatures. Hysteresis (±0.1°C to ±2°C dead band) available for simpler radiator systems.
🛁 Floor Sensor InputOptional ENGO EFS300 sensor connects to S1/COM — enables floor temperature limiting and "comfortable floor" mode for wood, laminate, and tiled floors.
🏨 Hotel Card InputVolt-free contact input on S1/S2 for hotel card readers — triggers eco setpoint on card removal, perfect for hotels, holiday lets, and serviced apartments.
❄️ Heat & Cool ModeSwitchable output for reversible heat pump and fan coil systems with both heating and cooling capability.
🔒 Min/Max Setpoint LimitsLock the temperature range via installer settings — protects against accidental extremes in rentals and commercial installations.
🛡️ 5-Year WarrantyFull 5-year ENGO manufacturer's warranty.
Suitable For
Wet Underfloor Heating
Gas & Oil Boilers
Heat Pumps (on/off)
ENGO ECB62-ZB Control Box
Zone Valves & Wiring Centres
New-Build Smart Home Installations
Multi-Zone ZigBee UFH Systems
Hotels & Serviced Apartments
Managed Rental Properties
Commercial UFH & Boiler Control
Bathroom & Wood Floor Rooms
Fan Coil Units (Heat & Cool)
About the EONE-230B
The EONE-230B is the permanently installed, mains-powered member of the ENGO ONE family. It fits a standard 60 mm flush back box: the total installed depth (thermostat + back box) is 34 mm, while the front plate sits just 13.5 mm above the wall surface. The 90 × 90 mm square format aligns with standard UK single-gang back boxes and matches the footprint of conventional thermostats — a true drop-in replacement that upgrades any existing installation to full ZigBee smart control.
⚡ Direct Wired Output — When You Don't Need a Separate Receiver
The EONE-230B's 3(1)A volt-free COM/NO relay output means it can directly control a wiring centre input, standard zone valve, or small heating load without any additional relay module. This simplifies installations: wire the thermostat to 230V for power, and take the COM/NO output straight to the boiler, wiring centre, or zone valve. For ENGO ECB62-ZB control box installations, use the ZigBee Binding function instead — the wired relay output and ZigBee control can coexist, giving maximum flexibility across different installation types.
Like all ENGO ONE thermostats, the EONE-230B supports ENGO Binding — a direct ZigBee link to a compatible receiver (ECB62-ZB or EMOD-ZB) that operates without the gateway or internet. Once bound, heating control is reliable and independent of cloud connectivity, with the app and voice control as additional layers on top rather than dependencies.
The S1/COM input accepts the optional EFS300 NTC floor sensor for floor temperature protection and "comfortable floor" mode. The S1/S2 terminals also support a hotel card reader — useful in serviced apartments, hotels, and holiday lets where you want heating to drop to a frost-protection setpoint when the room is vacated. Both functions are configured via the installer settings menu.
Key Features
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ZigBee 3.0 wireless — EGATE-PRO or EGATEZB gateway required for app/cloud
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230V AC / 50Hz mains power — permanently on, no battery management
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Volt-free COM/NO relay output: 3(1)A — direct wired connection to wiring centre, zone valve, or control box
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Flush-mounted — standard 60 mm back box — 90 × 90 × 34 mm total (13.5 mm above wall)
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Built-in humidity sensor — room RH% on display and in app
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ENGO Binding — direct offline ZigBee control of ECB62-ZB, EMOD-ZB
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TPI algorithm — or Hysteresis (±0.1°C to ±2°C), selectable
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Temperature setpoint range: 5°C – 45°C (display accuracy: 0.5°C)
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Heating and Cooling mode — switchable for heat pump / fan coil compatibility
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S1/COM floor/air sensor input — accepts EFS300 NTC sensor for floor protection
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Hotel Card input — S1/S2 volt-free contact for eco mode activation
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Min/max setpoint limits — configurable via installer settings
- Adjustable display backlight brightness
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ENGO Smart app (Tuya Cloud) — iOS & Android; Alexa & Google Home compatible
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Temperature history graphs in app
- Colour: Matt Black — white version: EONE-230W
- 5-year manufacturer's warranty
- EAN: 5904665764121
Technical Specifications
| Specification |
Detail |
| Model |
EONE-230B — Black |
| Mounting Type |
Flush-mounted — standard 60 mm back box |
| Power Supply |
230V AC / 50Hz |
| Control Output |
Volt-free COM/NO relay — 3(1)A |
| Temperature Setpoint Range |
5°C – 45°C |
| Display Temperature Accuracy |
0.5°C |
| Control Algorithm |
TPI — or Hysteresis (±0.1°C to ±2°C) |
| Humidity Sensor |
Yes — built-in |
| Sensor Input (S1/COM) |
Floor/air NTC temp sensor (EFS300) or volt-free contact (Hotel Card) |
| Communication |
ZigBee 3.0 |
| Gateway Required |
Yes — ENGO EGATE-PRO or EGATEZB (sold separately) |
| ENGO Binding |
Yes — direct offline control of ECB62-ZB, EMOD-ZB |
| App Platform |
ENGO Smart / Tuya Smart (Tuya Cloud) — iOS & Android |
| Voice Assistants |
Amazon Alexa, Google Home |
| Heating / Cooling Mode |
Yes — switchable |
| Offline Operation |
Yes — relay output continues locally; ENGO Binding for ZigBee receivers |
| Dimensions (flush) |
90 × 90 × 34 mm (13.5 mm above wall surface in 60 mm box) |
| Colour |
Matt Black |
| Warranty |
5 years |
| EAN |
5904665764121 |
Installation & Compatibility Notes
Installation must be carried out by a competent person in accordance with BS 7671 (IET Wiring Regulations) and the heating appliance manufacturer's instructions. The thermostat requires a standard 60 mm flush back box (not included). Connect L, N, and Earth to the thermostat's power terminals and the COM/NO volt-free output to the wiring centre, zone valve input, or boiler room thermostat terminals. The 3(1)A rating is suitable for standard wiring centre inputs and zone valves — for higher-load applications, use the EREL-16ZB relay in line.
For ZigBee smart features, pair via the EGATE-PRO or EGATEZB gateway. For ENGO Binding with the ECB62-ZB control box, follow the binding procedure in the installation guide. To use the floor sensor, wire the EFS300 to S1 and COM and select "Floor sensor" in the installer menu. To enable hotel card mode, wire the card reader volt-free output to S1/COM or S2/COM (depending on installer menu configuration).
Frequently Asked Questions
Do I need a separate receiver or relay module?
For wired control of a wiring centre, zone valve, or boiler input, the built-in 3(1)A COM/NO relay is sufficient — no additional receiver needed. For wireless ZigBee control of an ECB62-ZB or EMOD-ZB, the relay output is not used — the ZigBee Binding handles switching via the receiver. Both modes can coexist.
What is the difference between the EONE-230B and EONE-BATB?
The EONE-230B is flush-mounted and mains-powered (230V AC) with a physical COM/NO relay output — it permanently wires into the wall. The EONE-BATB is surface-mounted and battery-powered (rechargeable Li-Ion via USB-C) with no physical relay output — it pairs wirelessly with a separate receiver to switch the heating load. Both share identical ZigBee 3.0, app, humidity sensor, and TPI features.
Will it work with my existing wiring centre?
Yes — the volt-free COM/NO output is compatible with virtually all standard UK wiring centres (including Honeywell, Heatmiser, Salus, and others) that accept a room thermostat input. Wire to the thermostat input terminals on the wiring centre exactly as you would with any standard programmable thermostat.
Do I need a ZigBee gateway?
A gateway (EGATE-PRO or EGATEZB) is required for app access and voice control. Without a gateway, the thermostat still works as a standalone local programmable thermostat using its relay output and onboard controls — smart features just won't be available.
Can I use it in a hotel or holiday let?
Yes — the hotel card input is specifically designed for this use case. Wire a volt-free card reader output to S1/COM and configure hotel card mode in the installer settings. When a guest removes the card, the thermostat drops to an eco/frost-protection setpoint. App-based min/max limits also allow the property owner to cap the temperature range guests can set.
What's in the Box
- ENGO EONE-230B thermostat (matt black)
- Wall-mounting screws and fixings
- Quick start guide (multilingual, English included)
⚠️ Please Note: Wiring must be carried out by a competent person in accordance with BS 7671. Requires a standard 60 mm flush back box (not included). A ZigBee gateway (EGATE-PRO or EGATEZB, sold separately) is required for app and voice control features. White version available: ENGO EONE-230W. Battery-powered version available: ENGO EONE-BATB.
