K5 WiFi Smart Thermostat with VA Colour Display

Overview

The SunAura K5 is a wall-mounted WiFi smart thermostat purpose-built for floor heating control. Its white square 86×86 mm face carries a vivid VA colour screen on a black background, and five tactile front keys (power, sun/mode, program/clock, up and down) keep everyday control simple even without a phone. What sets the K5 apart is its dual load architecture: the same wall plate switches a 16 A electric underfloor heating circuit directly, or — in the boiler version — closes a 3 A NO dry contact to fire a water underfloor system or wall-hung gas boiler.

Where the K5 really earns its place is control. It joins your home WiFi network and the Tuya-compatible smart home app, so you can run a weekly programme of up to six time periods per day (with separate weekday and weekend groups), pre-heat the house before you arrive, link heating to other smart-home scenes, trim energy use with the built-in energy-saving mode, and lock the keypad against children — all remotely, from anywhere in the world. The colour VA screen stays comfortably readable at night in a bedroom or hallway, and every setting survives a power cut thanks to non-volatile memory.

The K5 is manufactured by SunAura Thermal from our Qingdao factory, operating ISO-style quality management with more than 17 years of OEM/ODM experience supplying heating controls to 50+ countries. Every unit is tested before shipment and carries CE, FCC and RoHS compliance.

Key Features

• VA colour display on black background — large room temperature, SET target temperature, clock, weekday and relative humidity shown in crisp segments that stay legible at night.
• Dual load coverage — 16 A resistive direct switching for electric underfloor heating, or a 3 A normally-open dry contact for water heating and gas boiler enable signals.
• Weekly programming, six periods per day — independent weekday and weekend programme groups, each time slot with its own target temperature, so heating follows your routine instead of running all day.
• WiFi remote control and scene linkage — full operation through the Tuya-compatible app on iOS and Android, with scheduled programmes, away mode and smart-scene integration.
• Energy-saving mode — the intelligent control chip widens the comfort differential when the house is empty, trimming consumption without sacrificing comfort on your return.
• Child lock — a lock symbol on the display and an app-side switch stop children or guests from accidentally changing settings.
• Power-off memory — programmes, set temperatures and calibration are retained permanently; no re-programming after a power cut.
• Antifreeze protection — a dedicated antifreeze symbol keeps the space above freezing, protecting pipes, boilers and holiday homes while you are away.
• Flame-retardant engineering housing — the case is moulded from PC+ABS flame-retardant plastic and fits the standard 86 mm wall box.
• Five front keys — power, sun/mode, program/clock, up and down, for intuitive local operation without opening the app.

Display & Icon Guide

The K5 VA screen communicates the full heating state at a glance. The large numerals on the left show the measured room temperature (marked ROOM TEMP), while the target temperature on the right always carries the SET label, so a measured reading is never confused with the programmed target. A blue-to-red arc temperature bar fills as room warmth rises, and the heating flame icon lights the moment the relay energises and the heat source is running.

Around the main reading you will find the week indicator (MON–SUN) showing the current day, the 24-hour clock, the home icon, the WiFi icon confirming cloud connection, the %RH humidity reading, and the AUTO / ON-OFF status text telling you whether the weekly programme is running or the unit is switched off. The hand icon marks manual hold mode, the program clock icon marks an active time-slot, the sun icon marks mode selection, the leaf icon marks energy-saving mode, the valve icon signals load output in the boiler version, and the child lock symbol confirms the keypad is locked. The small antifreeze symbol indicates freeze protection keeping the space above freezing — a heating safeguard only.

Physically the K5 measures 86×86 mm on the front face with a flush depth of about 14 mm and a total depth of about 26 mm, matching the standard 86-box mounting grid used across residential and light commercial installations.

Technical Specifications

Applications

The K5 is a universal floor-heating controller for residential and light commercial spaces:

• Home — living rooms, bedrooms, bathrooms and studies, paired with electric heating mats, cables and film, or with water underfloor loops driven by a wall-hung boiler.
• Office — open-plan workspaces and meeting rooms where weekly programmes match business hours and shut heating down on weekends automatically.
• Hotel — guest-room zoning, keycard-friendly scheduling and child-safe keypads for a tidy, low-maintenance installation.
• Market / retail — shop floors and showrooms where remote app monitoring and away-mode protection keep energy costs predictable across multiple units.

Installation

1. Mount the back plate — fix the K5 base to a standard 86 mm wall box at about 1.4 m height, away from direct sunlight, draughts and concealed heat sources.
2. Connect the supply — route the AC live and neutral to terminals 1 (L) and 2 (N); switch off the circuit breaker before wiring and observe the marked terminal order.
3. Connect the load — on the 16 A electric version, connect the underfloor heating loop to terminals 3 (N1) and 4 (L1); on the 3 A boiler version, connect the boiler’s enable wires across the NO dry-contact terminals, never mains load directly.
4. Connect the floor sensor — run the external NTC floor probe to sensor terminals 6 and 7, buried beneath the heating mat or cable where it reads true floor temperature.
5. Close, power up and pair — snap the front cover onto the base, restore power, and add the unit in the Tuya-compatible app over 2.4 GHz WiFi to finish remote configuration.

Wiring should be carried out by a qualified electrician, and the connected load must never exceed the rated output (16 A electric, or the boiler’s enable current across the 3 A dry contact). A dedicated installation guide and wiring diagram ship with every order, and SunAura engineers are available by messaging app for remote commissioning support.

Compatibility with SunAura Heating Systems

The K5 is the natural control partner for the full SunAura heating range. On the electric side it pairs directly with SunAura heating mats, double-conductor heating cables, graphene heating film and renovation kits; on the water side its 3 A dry contact enables any wall-hung gas boiler or water underfloor manifold actuator, letting one thermostat family cover both system types on a project. When you order film, mat, cable or a matched boiler interface from SunAura, we can pre-configure the K5’s temperature limits, floor-sensor selection and weekly schedule to match your exact floor build-up, and supply the complete package — heat source, thermostat, insulation and accessories — from a single factory source with one warranty.

Quality, Certification & Support

SunAura Thermal has manufactured heating controls and electric heating products since 2008 from our Qingdao factory, operating ISO-style quality management with in-line testing on every thermostat batch. The K5 is CE, FCC and RoHS compliant, with certification documents available for review before purchase. We support distributors, installers and OEM customers with private-labelled branding, custom weekly programmes, packaging design and drop-ship logistics to more than 50 countries — plus direct after-sales help with spare parts, calibration guidance and commissioning support in English, German, French and Chinese.

FAQ

1. Which K5 version do I need — the 16 A electric model or the 3 A boiler model?

Choose the 16 A version if you are switching electric underfloor heating directly — heating mats, cables, graphene film or heating panels within the 16 A resistive limit. Choose the 3 A version if your heat source is a water underfloor system or a wall-hung gas boiler: the K5 then closes a volt-free NO dry contact to enable the boiler rather than switching the heating load itself. If your project mixes both, use one K5 per zone and tell us the system type when ordering.

2. How do I set the weekly programme?

Press the program/clock key on the device or open the timer screen in the Tuya-compatible app. The K5 stores up to six time periods per day, with separate weekday and weekend groups; set the wake, leave, arrive and bedtime slots and the target temperature for each, and the thermostat will run them automatically in AUTO mode.

3. Do I need the external NTC floor sensor?

Yes for floor-heating comfort control. The external NTC probe (β = 3950, R25°C = 10 kΩ) connects to terminals 6 and 7 and sits beneath the floor finish, so the K5 can limit floor temperature and heat the floor evenly. The built-in air sensor still reads room temperature; select which sensor controls the output in the device menu.

4. What happens to my settings during a power cut?

All programmes, set temperatures, sensor selection and calibration offsets are stored permanently in non-volatile memory. When power returns, the K5 resumes the last weekly programme and set temperature automatically — no re-pairing or re-programming needed.

5. Can I recalibrate the displayed temperature?

Yes. Use the temperature calibration option in the device menu or app to offset the reading against a reference thermometer — typically ±1 °C — compensating for the thermostat’s wall position or the sensor’s location. Control accuracy is held to ±1 °C after calibration.

6. How does the child lock work?

Activate it from the device keys or the app switch; the lock symbol appears on the VA screen and key presses no longer change settings. Deactivate it the same way when you need to adjust the programme, keeping hotel, family and commercial installations safe from accidental operation.

7. What is the maximum load the K5 can switch?

The 16 A electric version switches resistive heating loads up to 16 A (roughly 3,500 W at 220 V). The 3 A boiler version carries only the boiler enable signal across its dry contact — never connect mains heating load to it. If your electric load exceeds 16 A, add a contactor and tell us when ordering so we pre-wire the commissioning guidance accordingly.

8. What is the warranty and after-sales support?

Every K5 includes a 2-year warranty and direct after-sales support from SunAura — spare parts, configuration help and commissioning guidance by messaging app, in English, German, French and Chinese. Distributors and OEM customers also get private-labelling, custom programming and logistics support to 50+ countries.

Looking for a 16A WiFi thermostat for heating cable and electric mat projects, or a VA colour screen room controller for wall-hung boilers? The K5 covers both jobs from a single 86 mm wall plate: the 16 A resistive version switches electric underfloor heating directly, while the 3 A normally-open dry-contact version calls for heat from a water underfloor loop or a gas boiler. This page adds our factory-direct purchasing terms, customization options and the long-tail questions installers and distributors ask us most before ordering.

How to Buy the K5 — Factory-Direct Pricing

SunAura Thermal sells the K5 directly from our Qingdao factory to distributors, heating contractors, hotel project buyers and private-label brands, with wholesale price tiers that scale with your order volume. MOQ and pricing depend on the model (16 A electric or 3 A boiler version), quantity and destination market — send us your project list and we return a same-day quotation. Standard terms include tiered bulk discounts from trial orders up to full-container loads, EXW or FOB pricing on request, and CE, FCC and RoHS compliance documents supplied with every shipment. Evaluation samples are available before a bulk order; the sample and courier charge is confirmed per enquiry, and sample charges are typically credited against a later container order. Drop shipping to your installers is available in 50+ countries.

To request a quote or the current sample list, contact our sales team or message us on WhatsApp with your project type (electric floor, water underfloor or boiler) and estimated quantities. The full line-up of matching wall controllers is listed in our thermostats and controls category — including the colour-touch K9 smart thermostat for projects that prefer a glass touch interface, and our all-black glass touch WiFi thermostat for modern interiors.

Customization & OEM for Distributors

For distribution and brand customers, the K5 supports private-labelling: your logo on the faceplate or packaging, a weekly programme pre-matched to your local market’s schedule, and custom cartons with your artwork. We also pre-configure the floor-sensor selection, temperature limits and antifreeze thresholds per project, so installers receive a controller that is ready to commission rather than re-set on site. When you pair the K5 with SunAura heating mats, double-conductor cables or graphene film, the whole project — heat source, thermostat, NTC floor sensor and accessories — ships under one warranty and one after-sales contact. For rooms where humidity also matters, pairing the K5 with an indoor thermometer-hygrometer gives occupants a second climate readout alongside the thermostat’s own %RH display.

More Frequently Asked Questions

9. Can I switch the K5 from the 16 A electric version to the 3 A boiler version later?

No — the two versions use different relay hardware and terminal layouts, so the variant must be chosen at order time: 16 A resistive switching for heating mats, cables and film, or the volt-free NO dry contact for water underfloor loops and wall-hung gas boilers. If a project mixes both system types, fit one K5 per zone and tell us the system type for each zone when ordering; we will pre-wire the commissioning guidance to match.

10. Do you supply a K5 WiFi floor heating thermostat package with the floor sensor included?

The external NTC floor sensor (β = 3950, 10 kΩ at 25 °C, wired to terminals 6 and 7) is quoted as part of the complete heating package rather than a hidden extra. Send us your floor build-up and room sizes and we will quote the thermostat, sensor, heating mat or cable, insulation and accessories as one matched package from a single factory source. You can also browse the wider controller line-up in our thermostat range before you decide.

11. Is a private-label WiFi floor heating thermostat available for resale?

Yes. SunAura has more than 17 years of OEM/ODM experience and offers private-labelled K5 units with your logo, custom packaging and pre-set weekly programmes for distributors, heating brands and hotel procurement teams. Certification documents (CE, FCC, RoHS) and project quotations are prepared on request — start by contacting our sales team, and check our main FAQ page for answers on lead times, shipping and commissioning. Real installation scenarios across electric and hydronic floor projects are shown in our applications gallery, so you can see how this VA colour screen floor heating controller performs in living rooms, bathrooms, offices and hotel rooms.

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