ATTACK Wall-mounted fan-coil unit FCU - W 4 (5.4/3.6 kW)
Code: FCUW4Product detailed description
The ATTACK Wall-mounted fan-coil unit FCU - W 4 (5.4/3.6 kW) is a wall-mounted fan-coil unit from the FCU - W 4 series, designed to distribute heat and cold from a heat pump (e.g. ATTACK Inverter R32 Air/Water) directly into residential or commercial spaces. The unit achieves a cooling capacity of approx. 5.4 kW and a heating capacity of approx. 3.6 kW, and is powered by a modern direct current (DC/EC) fan motor with continuously variable speed control.
Key features
- Wall-mounted installation - mounted directly on the wall similarly to a classic wall-mounted (split) air conditioning unit, air is drawn in from the front/top and blown into the room through adjustable louvres - suitable where no ceiling void is available or where simpler installation and filter maintenance is required
- Cooling capacity approx. 5.4 kW, heating capacity approx. 3.6 kW (at rated conditions)
- DC (EC) fan motor - low electricity consumption, quiet and smoothly controllable operation
- Built-in condensate collection tray with drain connection for cooling mode
- Replaceable/washable air filter that captures dust and coarse impurities
- Rated air flow of approx. 750 m³/h at the highest fan speed
- Option of independent room control using a thermostat/controller and a motorised valve on the water supply
- Suitable as a terminal (distribution) unit for both the heating and cooling system with a heat pump
How a fan-coil unit works
A fan-coil unit is a water heat exchanger fitted with a fan that draws room air through a finned coil. In summer, chilled water from a heat pump operating in cooling mode flows through the coil, the air is cooled and dehumidified, and the unit returns it to the room - the resulting condensate is drained via the collection tray and drain connection. In winter, hot heating water can instead flow through the coil, and the unit serves as a supplementary or main heat source for the room, with a faster response than, for example, underfloor heating.
Thanks to the DC (EC) motor, the fan speed can be smoothly adjusted to the current capacity requirement and to the need for quiet operation (e.g. in night mode in a bedroom), while keeping the fan's own electricity consumption low.
Overview of the ATTACK FCU fan-coil unit range
The ATTACK FCU range offers both cassette (ceiling) and wall-mounted versions in several capacity levels, so that a suitable unit can be chosen for rooms of different sizes. The ATTACK Wall-mounted fan-coil unit FCU - W 4 (5.4/3.6 kW) model is part of this range.
| FCU - C 2 / C 3 | cassette, smaller cooling capacity approx. 3.1 / 4.7 kW - smaller rooms |
| FCU - C 4 / C 5 / C 6 | cassette, medium cooling capacity approx. 5.9 - 9.0 kW - larger rooms, living rooms |
| FCU - C 8 | cassette, highest cooling capacity in the range approx. 11.6 kW - large spaces, open-plan offices |
| FCU - W 2 / W 3 | wall-mounted, smaller cooling capacity approx. 2.7 / 4.1 kW - bedrooms, smaller rooms |
| FCU - W 4 / W 5 | wall-mounted, higher cooling capacity approx. 5.4 / 6.8 kW - living rooms, larger rooms |
Choosing a suitable room and location
When choosing the location for a fan-coil unit, it is necessary to take into account the room's heat load (area, window orientation, glazed surfaces, number of occupants), an unobstructed airflow path (furniture, curtains) and the availability of water and electrical connections. For cassette versions, sufficient clear ceiling height must be available for the unit body itself and for service access, while for wall-mounted versions it is advisable to place the unit in the upper third of the wall with a clear view into the room.
Installation and use
The ATTACK Wall-mounted fan-coil unit FCU - W 4 (5.4/3.6 kW) is connected to the heating/cooling water pipework via a G 1/2" threaded connection; we recommend fitting shut-off ball valves for servicing purposes and a motorised 2-way or 3-way valve to regulate flow according to the current heat load of the room. Condensate drainage must be arranged either by gravity fall to a drain, or using a condensate pump if a gravity fall is not available. The unit weighs approx. 15.5 kg, with approximate dimensions of 900x195x600 mm (W×D×H, estimate). Before first start-up, we recommend having the connection checked by a qualified professional.
Control and operation options
The unit can be fitted with a wired room controller with a display, a wireless remote controller, or integrated into a higher-level building management system. Control typically allows setting the desired temperature, selecting the fan speed level and switching between heating and cooling mode (in systems with 4-pipe or switched 2-pipe distribution). The specific type of controller and its functions should be chosen according to the design of the heating/cooling system.
Energy efficiency and operating costs
Thanks to the DC (EC) fan motor, the electricity consumption of the ATTACK Wall-mounted fan-coil unit FCU - W 4 (5.4/3.6 kW) unit itself is significantly lower than with older types with an AC motor, especially at partial load. Since the fan-coil unit only distributes heat/cold generated by the heat pump and does not generate heat itself, its operating costs mainly consist of fan consumption - the actual energy consumption for heating/cooling depends primarily on the efficiency of the connected heat pump.
Practical application examples
Summer cooling of a living room: The ATTACK Wall-mounted fan-coil unit FCU - W 4 (5.4/3.6 kW) connected to an ATTACK Inverter R32 heat pump operating in cooling mode can significantly improve thermal comfort in a room during hot summer months, where underfloor heating alone provides no or only limited cooling effect.
Fast heating boost in the transitional season: In spring and autumn, when outdoor temperatures fluctuate, a fan-coil unit provides a faster response to changes in the desired temperature than the more sluggish underfloor heating, which is especially appreciated in rooms with variable occupancy (living room, study).
Compatibility with ATTACK heat pumps
The ATTACK Wall-mounted fan-coil unit FCU - W 4 (5.4/3.6 kW) is designed to work together with heat pumps from the ATTACK Inverter R32 Air/Water range, which can provide both chilled and hot heating water needed for the unit's cooling and heating modes. When multiple fan-coil units are installed in a building, we recommend connecting them via a hydraulic manifold or a buffer/accumulation tank (e.g. ATTACK AK ANTIKOR), which stabilises the flow and protects the heat pump from unwanted compressor cycling when several circuits open/close simultaneously.
Air quality and filtration
Before contact with the heat exchanger, the intake air passes through a replaceable/washable filter that captures coarser dust and impurities, protecting the finned coil from clogging and extending the interval between deep cleanings of the unit. In addition, when operating in cooling mode, the air in the room is partially dehumidified, which in summer months contributes to a better sense of thermal comfort even at the same air temperature. For higher air quality requirements (allergy sufferers, dustier environments), a finer supplementary filter may also be considered, if the given model and controller allow it.
Safety and installation notes
The electrical connection of the unit (fan, and condensate pump if applicable) must be carried out by a qualified professional in accordance with applicable electrotechnical standards. Condensate drainage must be routed with a fall away from living spaces, or through a working condensate pump, to prevent water leaking into the building structure. Before first start-up, we recommend performing a pressure test of the water circuit.
Environmental and sustainability aspect
Thanks to the DC (EC) fan motor, the ATTACK Wall-mounted fan-coil unit FCU - W 4 (5.4/3.6 kW) unit consumes less electricity than comparable versions with an older AC motor, especially when operating at partial load. Since the unit only distributes heat/cold and does not generate it (this is provided by the connected heat pump), its environmental benefit lies mainly in the efficient use of already generated energy without unnecessary losses.
Delivery and handling
The product is delivered by pallet freight, usually within a few working days of ordering (we will confirm the exact delivery date after receiving your order, as some models are manufactured or assembled to order). Given the product's weight (approx. 15.5 kg), we recommend arranging suitable handling equipment (pallet truck, or a second person) when receiving the shipment, and checking that the packaging is undamaged upon receipt, in order to preserve any claim for damage caused during transport.
About the manufacturer ATTACK
ATTACK, s.r.o. is a Slovak manufacturer of heating and cooling technology, which complements its portfolio of ATTACK Inverter R32 heat pumps with related accessories including fan-coil units from the FCU series, buffer tanks and domestic hot water cylinders, in order to offer customers a complete heating and cooling solution from a single source.
Technical parameters
| Installation type | wall-mounted |
| Model | FCU - W 4 |
| Cooling capacity (estimate) | 5.4 kW |
| Heating capacity (estimate) | 3.6 kW |
| Fan motor type | DC (EC) - direct current, continuously variable control |
| Rated air flow | approx. 750 m³/h |
| Mounting method | wall-mounted |
| Dimensions (estimate) | 900x195x600 mm (W×D×H, estimate) |
| Weight (estimate) | 15.5 kg |
| Water connection | G 1/2" |
| Condensate drainage | collection tray + drain connection (condensate pump option available) |
| Manufacturer | ATTACK, s.r.o. |
| Country of origin | Slovakia |
| Warranty | 24 months |
Note: dimensions, weight and air flow are approximate estimates for this model in the FCU range; please verify the exact values in the manufacturer's current technical data sheet or request them when ordering.
Frequently asked questions
How does a fan-coil unit work together with a heat pump?
A fan-coil unit is a water heat exchanger with a fan that takes cold or hot water from a heat pump (e.g. ATTACK Inverter R32) and transfers it to the room through intense airflow - cooling in summer, and providing supplementary heat in winter. It is therefore a terminal (distribution) element of the heating/cooling system, not a standalone heat source.
Does condensate form during cooling, and how is it drained?
Yes, during cooling mode, moisture in the air condenses on the cooling coil. The unit is equipped with a condensate collection tray with a drain connection, which is connected to the drain either by gravity or via a condensate pump if a gravity fall is not available.
Why does the unit have a DC (EC) motor, and what is the benefit?
Compared to a classic alternating current (AC) motor, the direct current (DC/EC) fan motor offers smooth speed control, significantly lower electricity consumption and quieter operation, which is a significant advantage for year-round fan-coil operation in residential spaces.
What is the difference between the cassette and wall-mounted versions?
The cassette (C) version is installed in a suspended ceiling (usually a 600x600 mm module) and distributes air into the room via 4-way (or 1-way) grilles, which is suitable for larger rooms and where concealed installation is required. The wall-mounted (W) version is mounted on the wall similarly to a classic split air conditioning unit, and is simpler to install and to maintain (filter access).
Can a single fan-coil unit be controlled independently of the rest of the heating system?
Yes, units are typically fitted with their own room thermostat/controller (wired or wireless) and a motorised 2-way or 3-way valve on the water supply, so the temperature in the given room can be regulated independently of other circuits.
Is a buffer tank or accumulation tank needed before the fan-coil units?
Connection via a hydraulic manifold/buffer (accumulation) tank is recommended, for example from the ATTACK AK ANTIKOR range, which stabilises the flow and temperature of the water supplied to the individual fan-coil units and protects the heat pump compressor from frequent switching.
How noisy is the unit, and can it be regulated?
Thanks to the DC motor, several fan speed levels can be smoothly set - at the lowest level, operation is very quiet, suitable for example for a bedroom, while at the highest level the maximum declared cooling/heating capacity is achieved.
Can the unit be connected to a central control system (BMS) or an app?
Yes, most fan-coil unit controllers support connection to a bus (e.g. Modbus) or integration into a higher-level building management system (BMS), or via a gateway to a mobile app. The specific options depend on the type of controller chosen, which must be purchased separately according to the design.
How often does the filter need to be cleaned or replaced?
We recommend checking and cleaning (or replacing) the air filter at least twice a year, or more often when operating in a dustier environment. A clogged filter reduces the unit's air flow and can increase its noise level.
Can a fan-coil unit completely replace radiators, or does it only supplement heating?
In practice, fan-coil units are used in both ways - as a supplementary fast source of heat/cold alongside underfloor heating (mainly for summer cooling, which underfloor heating alone does not provide), or as the main heating and cooling element in a room. The choice depends on the overall design of the building's heating/cooling system.
Warranty and service
This ATTACK product is covered by a standard warranty period of 24 months from commissioning, but no more than 30 months from the date of dispatch from the factory. For selected products, and when commissioning is registered by an authorised service technician, an extended warranty can also be arranged - please check the specific conditions when ordering or with our sales department. Service and spare parts are provided by the network of authorised ATTACK service partners in Slovakia, and spare parts are usually in stock.
Before commissioning, we recommend having the connection and system filling checked by a qualified professional (heating engineer/service technician), in order to meet the conditions for full warranty coverage.
Summary
ATTACK Wall-mounted fan-coil unit FCU - W 4 (5.4/3.6 kW) - a wall-mounted fan-coil unit with a DC motor, cooling capacity approx. 5.4 kW and heating capacity approx. 3.6 kW, designed to distribute heat and cold from the ATTACK Inverter R32 heat pump into residential and commercial spaces.
Additional parameters
| Category: | ATTACK buffer tanks and fan coils |
|---|---|
| Warranty: | 2 years |
| Weight: | 15.5 kg |
| Model: | FCU - W 4 |
| Fan motor type: | DC (EC) |
| Water connection: | G 1/2" |
| Control: | room thermostat / controller (standalone) |
| Manufacturer: | ATTACK, s.r.o. |
| Country of origin: | Slovakia |
| Warranty: | 24 months |
| Mounting type: | wall-mounted |
| Cooling capacity (approx.): | 5.4 kW |
| Heating capacity (approx.): | 3.6 kW |
| Nominal air capacity: | approx. 750 m³/h |
| Dimensions (approx.): | 900x195x600 mm (W×H×D, approx.) |
| Weight (approx.): | 15.5 kg |
| Condensate drainage: | collection tray + drain outlet |
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About the company
The product ATTACK is manufactured using the most modern production technologies available to us. As the most significant Slovak manufacturer of heating technology with purely Slovak capital and a single owner, we fully understand that each production process is reflected in the lifespan of this product and, of course, in your satisfaction. Therefore, we use only the best – from special boiler sheet metal through precise laser cutting of materials, to the most important – waterproof welds, which we perform exclusively robotically in precise fixtures, thus eliminating the human factor. All ATTACK products are high-quality premium products made using the most modern technology based on the latest research. The products have quality certificates from renowned testing laboratories and meet the conditions for the allocation of state subsidies.
History of the company ATTACK
The production site of the company is located in the northern part of central Slovakia, about 20 km from the city of Žilina. Our company, which is engaged in the production of heating technology, started production in 1995 with stationary boilers and gradually expanded its production to today's level, where it produces a wide range of wall-mounted condensing boilers, stationary boilers, solid fuel boilers and TÚV tanks. The company ranks among medium-sized companies covering an area of approximately 5000 m2 covered area and about 1000 m2 uncovered area. Boiler production takes place in our own production halls and has its own development, design, sales and export to foreign markets.
Company profile and vision
“The main goal and philosophy of the company is to develop top products with the highest quality, functionality and design, which achieve the highest combustion efficiency with regard to the environment while maintaining a favorable price.“
The company ATTACK and product portfolio
We offer a wide selection of products that differ by type of fuel and power. All boilers are equipped with components from world manufacturers produced by the most modern technology, production controlled by camera and computer systems and tested by the most progressive devices and methods. In each group there is a wide range of choices both in modifications and in power. Boilers are mainly intended for heating of family houses, apartments and also larger businesses. The company profile includes a portfolio containing boilers for biomass, gas, electricity and accessories. In the production of boilers we use renewable energy source and that is photovoltaic panels with a power of 200kWp, which provide sufficient electrical energy for production.
Export and service
The company ATTACK exports its products to more than 51 countries around the world. Currently we export our products to all EU countries, Russia, USA, Canada and New Zealand. The biggest interest abroad is in modern wood gasifying and pellet and combined boilers, which are currently very popular in Europe and on the American continent as well as in stationary gas boilers, which reliably represent us even in distant Siberia.
A special approach to each customer, accommodating negotiations and reliability quickly grow into mutual trust, which ensures us a constant growth of customers in other countries.
Our service partners are trained in our own training center, which is equipped with products involved in real operation. Our partners are trained in two phases – theoretical and practical – where they have the opportunity to apply the theoretical part into practice and try everything on the products.The company ATTACK, s.r.o. covers the service network throughout the territory of Slovakia. In case of a breakdown, we can help you with up to 705 service organizations, whose professionally trained service technicians can quickly resolve any problem with an ATTACK product for heating of family houses, apartments or businesses.
Company profile – Research and development
The company ATTACK, s.r.o. has its own research and development center, where development and technical staff of the company annually innovate and prepare new heating technology devices. Emphasis is placed on the simplicity of device operation, modern design, environmental tolerance and minimal dimensions. All products are designed and developed in accordance with the relevant standards, specifications, legal and other regulations. The selection of components for ATTACK products is subject to the strictest criteria and only reliable and long-term operation verified components and materials from renowned suppliers can be used.
In development, ATTACK, s.r.o. does not cooperate with other manufacturers, but strives to always be one step ahead of the competition.
The company ATTACK – Certificates and awards
The company ATTACK, s.r.o. is the holder of the quality certificate ISO 9001:
- for the design and development of boilers,
- for the production of boilers,
- service of devices and boilers
We place high emphasis on the quality of our products. We are the holders of the quality management certificate ISO 9001 since 2003. This quality certificate of international directive certifies activities in research and development, production, design and operation of gas equipment. The approval certificate was approved and issued by the prestigious London-based auditing company Lloyd’s Register Quality Assurance.
The demanding requirements placed on the company are also evidenced by the need to defend the certificate from the certification company LRQA every 3 years.
This quality management system indicates the progressiveness and positive approach of the company ATTACK, s.r.o. to the customer, to whom it proves its quality of a purely Slovak traditional company. The management system also emphasizes the company's strategy, which leads to its compliance, further development and improvement. All ATTACK® products are high-quality premium products made using the most modern technology based on the latest research. The products have CE, TÜV, GOST certificates from renowned testing laboratories around the world.
We regularly participate in domestic and foreign exhibitions of heating technology, where the company has received a whole range of awards from honorable mentions to gold medals.