The fan "sucks" air from the room and directs it to the heat exchanger. An energy carrier flows through the heat exchanger (cold or hot water, depending on the season of the season).
Water circulating in the inner cavity of the heat exchanger takes or transfers heat to the air flowing along the outer cavity of the heat exchanger. At the exit of the fan coil, cooled or heated air returns to the room - the desired temperature.
As a coolant, fresh water or water can be used in the heat exchanger with the addition of a certain concentration of non-freezing solution coming from the chiller. The maximum working pressure of the coolant is 1.6 MPa.
Fresh water or water with a concentration of non-freezing solution coming from the district heating network is also used as a heat carrier. Also, electric heating elements (thermal heating elements) can be used as heating elements. Thermal heating elements are installed as an additional option to two-pipe fan coil units.
Fancoil can operate both in air recirculation mode and in mixed mode, that is, connect the air from the room with fresh prepared air from the central air supply system.
In the air cooling mode, when warm air comes into contact with the cooled surface of the heat exchanger, condensate appears on the heat exchanger, which collects in a pan and flows by gravity into the drainage system.

In fan coil units manufactured by the HOTCHA Company, an increased capacity pan is developed that eliminates the possibility of condensate overflowing over the sides of the pallet at different heel and trim values of the vessel. The pallet has additional thermal insulation.
Condensation may also form on the surface of the fan coil housing. To prevent this phenomenon, fan coil housings are coated with an adhesive-based foam-based polyurethane insulation material. The use of this material also allows to reduce the level of aerodynamic noise in the surrounding space.
To regulate the performance, a regulating mixing unit is used, which makes it possible to dose the required amount of heat / coolant into the fan coil, thereby influencing the set parameters of the outlet air. At the same time, it is possible to regulate the air flow rate of the fan. Fancoils have at least three fan speeds. To achieve maximum heat / cooling capacity, it is recommended to connect the heat / coolant connection countercurrently to the air flow.

By design features, fancoils can vary:
- on two-pipe, incorporating one heat exchanger (work only on cold or only heat);
- four-pipe, incorporating two heat exchangers (simultaneous work on heat and cold groups of identical fan coil units in the off-season).
- Ceiling. They are installed horizontally in the ceiling space and distribute air through the air distributors along the ceiling.
- Floor standing. Installed vertically with a slight indent from the floor with installation on the bulkhead. Air distribution is carried out vertically through the air distribution device.
- High pressure. Having a dynamic pressure to overcome the network resistance with a pressure loss of up to 80 Pa.
- Low pressure. Overcoming network resistance with a pressure loss of up to 40 Pa.

The climatic modification, the category of placement and the operating conditions of the fan coil units in terms of the impact of climatic factors correspond to the OM design and categories 3-4 according to GOST 15150-69.
Fancoils work reliably with the following parameters:
- winter period - from minus 30 ° С at a humidity of 85%.
- summer period - up to plus 45 ° С at a humidity of 95%.
The coating of parts and assemblies in the device provides corrosion resistance, reliable operation and decorative appearance of the device during operation.
The performance of fan coils is ensured by the following mechanical influences:
- rolling onboard with a period of 7 ... 9 s, amplitude up to 22.5 °;
- pitching with a period of 5 ... 7 s, amplitude up to 10 °;
- roll long up to 15 °;
- trim long up to 5 °;
- vibration acceleration with an amplitude of up to 2g;

Fan coil design provides:
- free access to areas of maintenance and repair;
- rational dismemberment of components and their ease;
- recoverability to the state stipulated by the technical conditions for repaired fan coil units.
Fancoils are manufactured under the supervision of an inspector RMRS or RRR and have a certificate of type approval, as well as a manufacturer's quality certificate.

The delivery set includes reciprocal connections for connecting ship pipelines (counterflanges).
Also included are filter inserts for air purification, a set of spare parts for two years of operation and the necessary fasteners.
Fancoils come with the following documentation:
- technical description;
- instructions for the operation and repair of equipment;
- installation instructions;
- electrical schematic diagrams of connections and connections;
- a list of monitored parameters issued to IASU;
- a list of spare parts;
- instructions for acceptance, transportation, storage, reconservation, commissioning;
- passports, forms;
- drawing with overall and mounting dimensions;
- An electronic model of a fan coil in three-dimensional format.