ATTACK Outdoor Temperature Sensor for ACKT, ACKST, ACKZT

Product detailed description

ATTACK Outdoor Temperature Sensor is a simple yet highly effective accessory that significantly improves the comfort and operating efficiency of ATTACK wall-mounted gas boilers of the ACKT (KT 20 / 28 / 48), ACKST (KST 24) and ACKZT (KZT 25) series. It enables the boiler to operate in so-called weather-compensated control mode – i.e. automatically adjusting the heating water temperature according to the current outdoor temperature.

Why weather-compensated control makes sense

Without an outdoor sensor, the boiler keeps the heating water at a fixed set temperature regardless of whether it's -10 °C or +10 °C outside. This means the house gets overheated in milder weather (wasted gas consumption) or the temperature has to be lowered manually. With an outdoor temperature sensor, the boiler continuously evaluates how much heat the house actually needs and smoothly lowers or raises the heating water temperature accordingly. The result is a more stable room temperature, fewer unnecessary on/off burner cycles, and generally lower gas consumption.

Key features

• Measures outdoor temperature in the range -40 °C to +60 °C.
• IP54 protection rating – resistant to rain, dust and weather conditions.
• Simple 2-wire connection directly to the terminal block of the boiler's control board.
• Enables automatic adjustment of the heating curve according to outdoor temperature (weather-compensated control).
• Compatible with the entire range of ATTACK condensing boilers – ACKT20, ACKT28, ACKT48, KST24 and KZT25.
• Low purchase price with real energy-saving benefits.
• Easy installation without any intervention in the boiler's internal electronics.

Technical parameters

Installation and placement

The sensor is mounted on the outdoor facade of the building, ideally on the north or northwest side, out of direct sunlight, above the level of snow cover and away from windows, doors, chimneys or air conditioning units that could distort the measured temperature. The sensor cable is routed to the boiler room and connected to the terminal block designated for the outdoor sensor on the boiler's control board. After connecting, the weather-compensated mode must be activated in the boiler menu and the heating curve set according to the type of heating system (radiators or underfloor heating) and the building's heat loss – we recommend leaving this setting to an installation company.

Compatibility and related products

The sensor is compatible with all ATTACK condensing boilers with OpenTherm control – specifically ACKT20, ACKT28, ACKT48, KST24 and KZT25. We recommend combining it with a room thermostat (OT36A, OT36B or OT80 with the OT81 wifi modem) – the combination of weather-compensated control (outdoor sensor) and room correction (room thermostat) provides the most accurate and economical heating control.

Maintenance

The sensor does not require special maintenance – we recommend occasionally checking the mechanical fixing on the facade and the condition of the supply cable, especially after winter or strong wind.

Frequently asked questions

Is it worth buying an outdoor sensor if I already have a regular room thermostat at home?

Yes, both elements address different aspects and work best together – the outdoor sensor adjusts the heating water temperature according to the weather (fast, smooth reaction to changes in outdoor temperature), while the room thermostat fine-tunes according to the actual room temperature. The combination of both provides the best comfort and savings.

Where exactly should I install the sensor?

On the north or northwest facade of the house, away from direct sunlight, windows, doors and heat sources (e.g. air conditioning unit, chimney), so that the measured value best corresponds to the actual outdoor temperature.

Is installing the sensor difficult?

It is a simple installation of a 2-wire sensor to the boiler's terminal block, which a heating technician or electrician can handle within a few minutes. We recommend leaving the subsequent heating curve setting in the boiler menu to an installation company.

Does the sensor work with the KZT25 boiler as well, or only with the KT series?

The sensor is compatible with the entire range of ATTACK condensing boilers with OpenTherm control – i.e. ACKT20, ACKT28, ACKT48, KST24 and KZT25.

How long is the sensor cable and can it be extended?

The standard cable length is 2 m; if a longer run is needed, the cable can be extended with a suitable shielded conductor without loss of measurement accuracy.

Will my actual gas consumption decrease after installing the sensor?

In most installations, yes – weather-compensated control prevents unnecessary overheating in milder weather and reduces the number of burner on/off cycles, which in practice results in lower consumption. The exact amount of savings depends on the specific building and how the boiler was previously set.

Why weather-compensated control is a sensible investment

A heating system without weather-compensated control typically operates with a fixed heating water temperature that the user sets once (for example, at the start of the heating season) and leaves unchanged. The problem is that heat demand fluctuates significantly during the season – in November at +10 °C outside, the house needs much less heat than in January at -15 °C. Without an outdoor temperature sensor, the boiler cannot recognize this difference and either overheats the house unnecessarily in milder weather (wasting energy) or fails to heat sufficiently during severe frost if the temperature was set too low. The outdoor temperature sensor eliminates this blind spot – the boiler "sees" the outdoor weather and, based on a pre-set heating curve, continuously adjusts the heating water temperature precisely to the current need.

Typical use cases

Family house with radiator heating: A classic family house heated by radiators benefits most from weather-compensated control during transitional periods (spring, autumn), when the outdoor temperature changes from day to day – the boiler automatically lowers the water temperature when it warms up and raises it when it cools down, without any intervention from the household.

House with underfloor heating: Underfloor heating operates with lower heating water temperatures and greater thermal inertia, so precise, smooth control based on outdoor temperature is especially beneficial – it prevents temperature fluctuations in rooms while maximizing the use of the boiler's condensing technology.

Combination with a room thermostat: In a modern installation, the outdoor temperature sensor is usually combined with a room thermostat (e.g. OT36A) – the outdoor sensor handles the basic, fast adjustment of water temperature according to the weather, while the room thermostat fine-tunes small differences according to the actual temperature in the living space (e.g. the effect of sunlight, heat from household appliances, etc.).

Setting the heating curve

The weather-compensated (heating) curve is a setting that tells the boiler what heating water temperature to maintain at a given outdoor temperature. For example, at -10 °C outside, the water temperature may be set to 55 °C, while at +10 °C outside, water at only 30 °C is sufficient. The exact shape of the curve depends on the type of heating system (radiators generally require higher temperatures than underfloor heating), the building's heat loss, and personal thermal comfort preferences. We always recommend leaving this setting to an installation company, which will fine-tune the curve for the specific building, or adjust it slightly during the first heating season based on feedback from the occupants.

More frequently asked questions

Can an outdoor temperature sensor be retrofitted to a boiler that has already been in operation for several years?

Yes, the sensor can be installed additionally on an existing boiler without the need to replace the control electronics – it is enough to connect it to the appropriate terminal block and activate the weather-compensated mode in the boiler menu.

What happens if the sensor stops working or gets disconnected?

If the signal from the sensor is lost, the boiler usually switches back to the fixed heating water temperature (as if the sensor were not connected), so that heating functionality is maintained, although without the benefits of weather-compensated control – we recommend fixing the fault as soon as possible.

Does the heating curve need to be set again every season?

No, the curve is set once during installation and generally remains the same, unless there is a change in the heating system (e.g. insulating the house, replacing radiators) or a change in thermal comfort preferences.

Does the sensor also affect domestic hot water (DHW) preparation?

No, weather-compensated control applies exclusively to the heating water temperature for space heating. DHW preparation runs independently according to a separately set target hot water temperature.

Is the sensor resistant to frost and rain?

Yes, the sensor has an IP54 protection rating and is designed for permanent installation on the outdoor facade of a building, including winter months with frost, snow and rain.

Difference between weather-compensated and room control

It is important to distinguish between two different, yet complementary, heating control principles. Weather-compensated control (with an outdoor sensor) reacts to outdoor weather and adjusts the heating water temperature in advance, before the weather change is felt indoors – it is therefore a preventive, fast-reacting type of control. Room control (with a room thermostat), on the other hand, measures the actual result – the real room temperature – and fine-tunes it via feedback. The combination of both approaches (outdoor sensor + room thermostat) delivers the best results: the boiler reacts quickly to weather changes while also precisely fine-tuning according to what is actually happening in the living space.

Installation step by step (general procedure)

1. Choose a suitable location on the facade (north/northwest, away from direct sunlight and heat sources). 2. Mount the sensor on the wall using the supplied mounting material. 3. Route the sensor cable to the boiler room to the boiler's control board, protecting it from mechanical damage. 4. Connect both wires to the appropriate terminal block according to the boiler's manual. 5. Activate weather-compensated mode in the boiler menu and set a suitable heating curve according to the type of heating system. 6. Verify functionality by comparing the outdoor temperature displayed on the boiler's display with the actual temperature.

More frequently asked questions

Can I install the sensor myself?

Mechanical mounting on the facade is simple, but we recommend leaving the electrical connection to the boiler control board's terminal block and the activation of weather-compensated mode to a professional, since incorrect wiring or curve settings can lead to improper heating operation.

Does the length and routing of the cable affect measurement accuracy?

Not for reasonably short runs when using a suitable cable; it is important to avoid routing the cable alongside power electrical wiring, which could cause signal interference.

What is the difference between weather-compensated control and simply lowering the temperature at night?

Night setback (a simple blanket temperature reduction at a certain time) is only a time-based reduction, whereas weather-compensated control continuously reacts to the actual outdoor temperature regardless of time – both principles can be combined for even greater savings.

Does this investment pay off quickly?

Given its low purchase price and real benefit in reducing unnecessary overheating, this sensor is among the accessories with one of the fastest returns on investment among ATTACK boiler accessories.

Can I verify myself whether weather-compensated control is actually working after installation?

Yes, the boiler's display usually shows the current heating water temperature as well as the outdoor temperature measured by the sensor. As the outdoor temperature drops, the heating water temperature should gradually rise according to the set curve, and vice versa.

Should I relocate the sensor if I find it is in an unsuitable location (e.g. on the sunny side)?

Yes, if you find that the sensor is exposed to direct sunlight or other distorting influences, we recommend relocating it to a more suitable location (north/northwest) and consulting the situation with an installation company, which may also adjust the heating curve setting accordingly.

Summary

The outdoor temperature sensor is one of those seemingly small accessories that have a disproportionately large impact on heating comfort and efficiency. Its low purchase price, easy installation and real benefit in limiting unnecessary overheating make this sensor an almost essential part of every modern ATTACK condensing boiler installation.

When ordering a new ATTACK boiler of the KT, KST or KZT series, we recommend considering purchasing this sensor together with the boiler, so that weather-compensated control can be set up right from the first commissioning.

If you have any questions regarding the suitability of this sensor for your specific boiler model or combinations with other accessories (room thermostats, wifi modem), do not hesitate to contact us via the atria.sk customer center – we will be happy to help you choose the whole heating control setup.

Thank you for caring about the real benefit for your household even with such a seemingly small accessory – it is precisely such details that make a difference in overall heating efficiency.

We wish you pleasant and economical heating with your ATTACK boiler enhanced by this practical accessory.

Warranty

We provide a warranty period of 24 months for this ATTACK accessory from the date of sale to the end customer (according to the tax document), provided the conditions specified in the installation and operation manual are met and installation is carried out by a professionally qualified person. The warranty does not cover defects arising from improper installation, mechanical damage, unauthorized interference with the device, or connection outside the specified parameters. We recommend keeping the proof of purchase and installation record for any potential warranty claim.

This is one of the cheapest, yet in terms of price-to-benefit ratio, one of the most worthwhile accessories you can purchase for your ATTACK condensing boiler.