ST-302 Thermostat for multi control is used for temperature control of central air-conditioning fan coil units system and air hose system. By comparing the room temperature with the set temperature, then we can control the open and close of the electric control valve and electric ball valve for the fan coil at the terminal air conditioning. In this way, the room temperature can stay at a stable range. When more than one thermostat are not allowed to be installed at the terminal equipment, this product can control multiple thermostat.