WiFi Thermostat for Underfloor Heating 16A – Heatline HL-05

The Heatline HL-05 is a modern and easy-to-use WiFi thermostat for underfloor heating, suitable for controlling electric floor heating, room heating and compatible 230V heating or cooling equipment.

The thermostat has a built-in room temperature sensor and a slim external NTC 10k floor sensor, which is included in the package. During setup, you can choose whether the heating is controlled according to room temperature, floor temperature or both sensors simultaneously.

The HL-05 also works as an independent thermostat without a WiFi connection. After connecting it to the Smart Life app, the temperature can be monitored and adjusted remotely, and an automatic weekly schedule can be created.

The thermostat is available in white and black.

Three Temperature Control Options

The Heatline HL-05 supports three different sensor operating modes.

Control by Room Temperature

In this mode, the thermostat controls the heating according to the built-in room temperature sensor.

This mode is suitable for:

• electric radiators;
• convector heaters;
• room heating;
• applications where maintaining a stable air temperature is the main priority.

In this mode, the external floor sensor is not used to limit the floor temperature.

Control by Floor Temperature

In this mode, the heating is controlled according to the included NTC 10k floor sensor.

This option is suitable for:

• bathroom floor heating;
• hallway floor heating;
• kitchen floor heating;
• tiled floors;
• rooms where a specific floor temperature should be maintained.

Control by Room Sensor with Floor Temperature Limitation

In combined mode, the heating is controlled mainly according to the room temperature, while the floor sensor limits the maximum permitted floor temperature.

This mode is particularly important for:

• wooden floors;
• parquet;
• laminate flooring;
• vinyl flooring;
• other temperature-sensitive floor coverings.

The maximum floor temperature limit can be adjusted between +20 and +70°C. The permitted maximum temperature must always be selected according to the floor covering manufacturer’s instructions.

Remote Control with the Smart Life App

The Heatline HL-05 connects to a WiFi network and can be controlled through the Smart Life mobile app.

The app allows you to:

• view the current temperature;
• change the target temperature;
• switch the thermostat on or off;
• select the operating mode;
• create a weekly schedule;
• check whether heating or cooling is active;
• change settings through the internet;
• control the temperature of a home, holiday house or other building remotely.

The thermostat also works without a WiFi connection. In this case, it can be used as a standard thermostat through the touch screen.

The thermostat must be connected to the Smart Life app to configure the weekly schedule.

Automatic Weekly Schedule

A weekly schedule can be created in the Smart Life app. The thermostat then changes the temperature automatically according to the selected times.

For example, you can set:

• a higher temperature in the morning;
• a lower temperature during working hours;
• a comfortable temperature before arriving home;
• a lower temperature at night.

The weekly schedule helps avoid unnecessary heating when the room is not in use or when a higher temperature is not required.

Once the thermostat has been connected to WiFi, you can switch between the automatic weekly schedule and constant-temperature mode from the thermostat display.

Constant Temperature Mode

The HL-05 can also be used as a simple thermostat that continuously maintains the temperature selected by the user.

This mode is suitable when:

• a weekly schedule is not required;
• the thermostat is used in a bathroom;
• the room must remain at a constant temperature;
• WiFi control is not required.

The temperature can be adjusted directly from the thermostat’s touch screen.

Suitable for Electric Underfloor Heating

The Heatline HL-05 is suitable for controlling electric underfloor heating within the maximum permitted relay load of 16A.

The thermostat can control:

• underfloor heating cables;
• underfloor heating mats;
• infrared heating film;
• bathroom floor heating;
• hallway or kitchen floor heating;
• other compatible electric heating equipment.

If the current of the connected heating load exceeds 16A or the equipment has a high starting current, a separate contactor must be used.

Suitable for 230V Water-Based Underfloor Heating Actuators

The thermostat can also control a compatible 230V thermal actuator or valve on a water-based underfloor heating manifold.

In this application, the thermostat does not directly regulate the water temperature or flow. It switches the actuator on or off according to the measured room or floor temperature.

Before connection, check the actuator’s:

• operating voltage;
• wiring diagram;
• current consumption;
• control logic.

The HL-05 also includes an anti-seizing function that can periodically open a valve for a short time if it has remained closed for an extended period.

Heating and Cooling Modes

The Heatline HL-05 can be used not only for heating but also for controlling compatible cooling equipment.

The settings allow you to choose:

• heating mode, in which the relay switches on when the temperature falls;
• cooling mode, in which the relay switches on when the temperature rises.

When using cooling mode, make sure that the operating voltage, wiring diagram and electrical load of the controlled equipment are compatible with the thermostat.

Open-Window Detection

The open-window function helps reduce unnecessary energy consumption during ventilation.

If the room temperature drops quickly, the thermostat can detect a possible open window and temporarily limit the heating. This prevents the heating system from trying to compensate for heat loss through an open window at full power.

The activation temperature can be adjusted between +5 and +25°C, and the duration can be set between 5 and 60 minutes.

Child Lock

The thermostat has a child-lock function that helps prevent accidental changes to the settings.

Two locking modes are available:

• partial lock, which may still allow the thermostat to be switched on or off;
• full lock, which prevents settings from being changed from the screen.

The child lock is useful in homes, nurseries, hotels and public spaces.

Adjustable Screen Brightness

The screen brightness can be adjusted in standby mode.

Available options include:

• screen off;
• dim backlight;
• bright backlight.

This is useful in bedrooms or other rooms where a bright screen could be disturbing.

Adjustable Switching Differential

The hysteresis of the room sensor, meaning the temperature difference between switching on and switching off, can be adjusted.

The room sensor adjustment range is 0.5–2.5°C. When the floor sensor is used for control, the switching differential can be set between 1 and 9°C.

A smaller hysteresis maintains a more stable temperature but may cause the relay to switch more frequently. A larger hysteresis reduces the number of switching cycles but allows greater temperature variation.

Temperature Calibration

The measured temperature can be calibrated between −9 and +9°C.

Calibration can be used if the thermostat reading differs from a reliable reference thermometer.

Before calibrating, make sure the difference is not caused by the installation location, air movement, direct sunlight or the temperature of the wall.

Operation After a Power Failure

The thermostat settings allow you to choose how the device behaves after the power supply is restored.

The thermostat can:

• restore the operating state used before the power failure;
• remain switched off;
• switch on automatically after power is restored.

For normal use, restoring the previous operating state is usually the most practical option.

Technical Specifications

• Manufacturer: Heatline
• Model: HL-05
• Product type: WiFi thermostat for underfloor heating
• Control: Touch screen and Smart Life app
• Supply voltage: 90–240V AC
• Frequency: 50/60Hz
• Maximum relay load: 16A
• Built-in sensor: Room temperature sensor
• External sensor: NTC 10k, 1% accuracy
• Floor sensor: Included
• Sensor modes: Room sensor, floor sensor or both sensors
• Adjustable temperature range: +1 to +70°C
• Factory temperature range: +5 to +35°C
• Maximum floor temperature limit: +20 to +70°C
• Measurement accuracy: ±0.5°C
• Room sensor hysteresis: 0.5–2.5°C
• Floor sensor hysteresis: 1–9°C
• Temperature calibration: −9 to +9°C
• Operating modes: Heating and cooling
• Weekly schedule: Through the Smart Life app
• Child lock: Partial or full
• Open-window function: Yes
• Screen brightness: Adjustable
• Protection rating: IP20
• Central unit size: 55 × 55 mm
• Overall size with frame: 82 × 82 mm
• Colours: White and black
• Compliance: CE and RoHS
• Warranty: 2 years

Installation and Wiring

The thermostat is installed in a suitable flush-mounted electrical box and connected to the electrical supply.

Terminal connections:

• terminals 1 and 2 – power supply;
• terminals 3 and 4 – heating or cooling equipment;
• terminals 6 and 7 – external NTC 10k floor sensor.

The electrical supply must be completely disconnected before installation.

Installation and electrical wiring must be carried out by a qualified electrician. Incorrect wiring may damage the thermostat or connected equipment and may create a risk of electric shock or fire.

Important Information

• An NTC 10k floor sensor is included.
• The HL-05 does not support selecting floor sensors with other resistance values.
• When replacing an old thermostat, check the resistance of the existing floor sensor.
• The Smart Life app is required to configure the weekly schedule.
• Basic thermostat functions remain available without a WiFi connection.
• The IP20 protection rating does not mean the thermostat is moisture-resistant.
• In a bathroom, the thermostat must be installed in an appropriate dry zone.
• The maximum permitted load is 16A.
• A contactor must be used for higher loads or equipment with a high starting current.
• For wooden, parquet, vinyl or laminate flooring, set the maximum permitted floor temperature.
• Installation must be carried out by a qualified electrician.

When Should You Choose the HL-05 or HL-44?

Choose the Heatline HL-05 when:

• you need an affordable WiFi thermostat for underfloor heating;
• it is a new installation;
• you plan to use the included NTC 10k floor sensor;
• the existing floor sensor is NTC 10k;
• you require heating and cooling modes;
• you want Smart Life control and a weekly schedule.

Choose the Heatline HL-44 when:

• you are replacing an existing thermostat;
• the resistance of the existing floor sensor is not 10k;
• you need compatibility with 3K–47K floor sensors;
• you require a wider selection of operating and energy-saving modes;
• compatibility with various 55 × 55 mm design frames is important.

The Heatline HL-05 is a practical and affordable smart underfloor heating thermostat that combines simple local control, remote control from a smartphone and an automatic weekly schedule.