The emergence of large air conditioning systems based on central air conditioners and chillers puts forward certain requirements for ease of installation and maintenance of climatic parameters. Modern technologies make it possible to significantly simplify the management of fan coil units and transfer the entire workflow to automatic mode. A person only needs to set indicators of a comfortable microclimate once, and the devices will maintain and correct them depending on changes in the external air temperature.
Fan coil control principle
To work with the indoor units installed in each room, special units, panels and remotes are used. Having received a signal from sensors (controllers) about the need to make changes, the actuators give a command to drive the fan or a 3-way valve. As a result, the air cooling/heating process:
- pauses when the set temperature is reached, when the fan turns off or reduces speed;
- resumes when the room temperature falls or falls below the set level.
With the help of modern automatic adjustment schemes, fan coil units can perform the following functions without human intervention:
- temperature programming;
- switching modes, for example, cold / heat, comfort / economy;
- fan speed selection;
- blinds adjustment and air destratification;
- opening/closing of 2-way or 3-way valves;
- timer programming (changing parameters at a certain time, reducing power or turning off fan coil units at night, as well as on weekends);
- turning on and off the heating element (if any);
- monitoring the condition of filters and signaling the need to clean or replace them.
Various built-in and remote panels can provide different types of control:
- mechanical (buttons and toggle switches for setting modes);
- electronic (automatic switching of temperature modes, turning on / off the fan, smooth change of its speed or power of the heat exchanger, etc.);
- microprocessor (additional features for quick reprogramming and prompt response to changing external conditions).
Such panels can be included in the design of the fan coil unit or installed separately from it, most often on the wall. Built-in panels are mainly equipped with floor models due to easier access to the device itself.
The remote control is considered more convenient to use, with which you can easily adjust the operation if the fan coil unit is installed in a hard-to-reach place (cassette, duct, ceiling models). According to the principle of operation, digital and infrared, wired or wireless remote control devices are distinguished.
Remote thermostats are used as remote controls in many systems, which send a signal to a common control board and correct the operation of the air conditioning system without requiring extra costs. For two-pipe and four-pipe systems, different versions of thermostats (mechanical and electrical) are used. The simplest ones only control the fan speed, but most are also capable of opening and closing valves.
The choice of control method can be chosen by the user directly at the time when the installation of fan coil units is being carried out or after its completion. Depending on the type of installation, the design of the door closer and its location, a built-in or remote panel, a remote control is selected. For large rooms, several fan coil units can be purchased and connected to a common building management system via a computer network.