ATTACK Cassette Fan-Coil Unit FCU - C 8 (11.6/7.5 kW, DC motor)

Product detailed description

ATTACK Cassette fan-coil unit FCU - C 8 (11.6/7.5 kW, DC motor) is a cassette (ceiling-recessed) fan-coil unit from the FCU - FCU - C 8 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. 11.6 kW and a heating capacity of approx. 7.5 kW, driven by a modern direct current (DC/EC) fan motor with smooth speed control.

Key features

• cassette (ceiling-recessed) installation - mounted into a suspended ceiling, standard module 600x600 mm, with air distribution to the room via a four-way (or one-way) discharge grille and central intake - suitable especially for offices, retail and residential spaces with a suspended ceiling where hidden, aesthetic installation is required
• Cooling capacity approx. 11.6 kW, heating capacity approx. 7.5 kW (at rated conditions)
• DC (EC) fan motor - low electricity consumption, quiet and smoothly adjustable operation
• Built-in condensate collection tray with drain connector for cooling mode
• Replaceable/washable air filter capturing dust and coarse impurities
• Rated air flow approx. 1700 m³/h at the highest fan speed
• Option of independent room control using a thermostat/controller and motorised valve on the water supply
• Suitable as a terminal (distribution) element of a 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 air from the room 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 connector. In winter, warm heating water can instead flow through the coil, and the unit serves as an additional or main heat source for the room, with faster response than, for example, underfloor heating.

Thanks to the DC (EC) motor, the fan speed can be smoothly adjusted to match the current output requirement and 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 series

The ATTACK FCU series offers cassette (ceiling-recessed) and wall-mounted versions in several capacity levels, so a suitable unit can be chosen for rooms of different sizes. The model ATTACK Cassette fan-coil unit FCU - C 8 (11.6/7.5 kW, DC motor) is part of this series.

Choosing the right room and location

When choosing the location of a fan-coil unit, it is necessary to consider the thermal load of the room (floor area, window orientation, glazed areas, number of occupants), an unobstructed airflow path (furniture, curtains) and the availability of water and electrical connections. For the cassette version, sufficient clear height above the suspended ceiling must be allowed for the unit body itself and for service access; for the wall-mounted version, positioning in the upper third of the wall with a clear view into the room is recommended.

Installation and use

The ATTACK Cassette fan-coil unit FCU - C 8 (11.6/7.5 kW, DC motor) connects to the heating/cooling water supply via a G 1/2" threaded connection; we recommend fitting shut-off ball valves for servicing and a motorised 2-way or 3-way valve to regulate flow according to the room's current thermal load. Condensate drainage must be arranged either by gravity fall to the sewer, or using a condensate pump if a gravity fall is not available. The unit's weight is approx. 36.5 kg, approximate dimensions 600x600x260 mm (cassette body) + approx. 850 mm extension above the ceiling. Before first start-up, we recommend having the connection checked by a professionally qualified person.

Control options

The unit can be complemented 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 (for systems with 4-pipe or switchable 2-pipe distribution). The specific type of controller and its functions should be selected 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 Cassette fan-coil unit FCU - C 8 (11.6/7.5 kW, DC motor) itself is significantly lower than with older AC motor types, especially at partial output. Since the fan-coil unit only distributes the heat/cold produced by the heat pump and does not generate heat itself, its operating costs consist mainly of the fan's consumption - the actual energy consumption for heating/cooling depends primarily on the efficiency of the connected heat pump.

Practical use examples

Summer cooling of a living room: The ATTACK Cassette fan-coil unit FCU - C 8 (11.6/7.5 kW, DC motor) connected to an ATTACK Inverter R32 heat pump operating in cooling mode can significantly improve thermal comfort during hot summer months in rooms where underfloor heating alone provides no or only limited cooling effect.

Fast additional heating in transitional periods: In spring and autumn, when outdoor temperatures fluctuate, the 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, home office).

Compatibility with ATTACK heat pumps

The ATTACK Cassette fan-coil unit FCU - C 8 (11.6/7.5 kW, DC motor) is designed to work with heat pumps from the ATTACK Inverter R32 Air/Water series, which can supply both chilled and warm 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/balancing tank (e.g. ATTACK AK ANTIKOR), which stabilises the flow and protects the heat pump from unwanted compressor cycling when several circuits open/close at the same time.

Air quality and filtration

Before contact with the coil, the intake air passes through a replaceable/washable filter that captures coarser dust and impurities, protecting the finned coil from fouling and extending the interval between deep cleanings of the unit. In addition, during cooling mode operation, the air in the room is partially dehumidified, which in summer months contributes to better perceived thermal comfort even at the same air temperature. For increased 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, possibly condensate pump) must be carried out by a professionally qualified person in accordance with applicable electrical standards. Condensate drainage must be routed with a fall away from living spaces or via a functioning condensate pump to prevent water leakage into the building structure. Before first start-up, we recommend performing a pressure test of the water circuit.

Ecological and sustainability aspect

Thanks to the DC (EC) fan motor, the ATTACK Cassette fan-coil unit FCU - C 8 (11.6/7.5 kW, DC motor) consumes less electricity than comparable designs with an older AC motor, especially when operating at partial output. Since the unit only distributes heat/cold and does not generate it (this is provided by the connected heat pump), its ecological benefit lies primarily in the efficient use of already produced energy without unnecessary losses.

Delivery and handling

The product is delivered by pallet transport, usually within a few business 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. 36.5 kg), we recommend arranging suitable handling equipment (pallet truck, or a second person) when receiving the shipment, and checking the packaging for damage upon receipt in order to preserve any possible claim for transport damage.

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 DHW cylinders, in order to offer customers a complete heating and cooling solution from a single source.

Technical parameters

Note: dimensions, weight and air flow are approximate estimates for this FCU series model; check exact values in the manufacturer's current 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 warm water from a heat pump (e.g. ATTACK Inverter R32) and, through intensive air flow, transfers it into the space - cooling in summer and providing additional heating 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, air humidity condenses on the cooling coil. The unit is equipped with a condensate collection tray with a drain connector, which is connected to drainage 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, a 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 mounted into 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 hidden installation is required. The wall-mounted (W) version is mounted on the wall, similar to a classic split air conditioning unit, and is simpler to install and maintain the filter.

Can a single fan-coil unit be controlled independently of the rest of the heating system?

Yes, the 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 a given room can be regulated independently of other circuits.

Is a buffer tank or balancing tank needed before the fan-coil units?

Connection via a hydraulic manifold/balancing (buffer) tank is recommended, for example from the ATTACK AK ANTIKOR series, which stabilises the flow and temperature of the water supplied to the individual fan-coil units and protects the heat pump compressor from frequent cycling.

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 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 chosen type of controller, which must be purchased separately according to the project.

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, more often in dustier environments. 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 both ways - as an additional fast source of heat/cold alongside underfloor heating (especially 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 brand 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; spare parts are usually in stock.

Before commissioning, we recommend having the connection and system filling checked by a professionally qualified person (heating engineer/service technician) to meet the conditions for full warranty coverage.

Summary

ATTACK Cassette fan-coil unit FCU - C 8 (11.6/7.5 kW, DC motor) - a cassette (ceiling-recessed) fan-coil unit with DC motor, cooling capacity approx. 11.6 kW and heating capacity approx. 7.5 kW, designed to distribute heat and cold from the ATTACK Inverter R32 heat pump into residential and commercial spaces.