According to the structural form, they can be divided into: vertical, horizontal, wall-mounted, and cassette types, among which the vertical type is further divided into column type and low type; according to the installation method, they can be divided into surface-mounted and concealed type; according to the water inlet position, they can be divided into left type and right type. All wall-mounted fan coil units are surface-mounted units, with a compact structure and good appearance, and are directly hung on the top of the wall. The cassette (ceiling-embedded) unit has a relatively beautiful air inlet and outlet exposed under the ceiling, and the fan, motor and coil are placed on the ceiling, which belongs to the semi-surface-mounted unit. Surface-mounted units have a beautiful outer shell, with their own air inlet and outlet, and are installed in the room. The outer shell of the concealed unit is generally made of galvanized steel plate.
The national standard "Fan Coil Units" (GB/T 19232-2019) [2] stipulates that fan coil units are divided into two categories according to the external static pressure: low static pressure type and high static pressure type. The low static pressure unit has an outlet static pressure of 0 or 12 Pa at rated air volume. For units with air outlets and filters, the outlet static pressure is 0; for units without air outlets and filters, the outlet static pressure is 12 Pa. High static pressure units are tested as if they were without air outlets and filters.
