FRB-541 fcu relay box is your best solution for controlling the Fan coil unit, it comes with 4 relays (high duty) for speeds and the heater,
with interfacing contact between it and the fire alarm system through the FAP
point main usage of it to disconnect the fan in case of fire by connecting it with fire alarm system control module,
also can be used for saving energy mode, and internal transformer 24V AC in order to powering the PICV actuator.
Easy play and plug connecting the terminals of PICV, thermostat and the FAP point.