1. The temperature control system of the fresh air unit is composed of a proportional integral temperature controller, a temperature sensor installed in the air supply duct and an electric control valve. The function of the controller is to transmit the air supply temperature detected by the temperature sensor in the air supply duct to the temperature controller for comparison with the temperature set by the controller, and according to the results of PI calculation, the temperature controller sends an open/close valve signal to the electric control valve, so as to keep the air supply temperature within the required range.

2、電動調節閥與風機連鎖，以保證切斷風機電源時風閥亦同時關閉。電動調節閥亦可實現與風機的聯動 ，當風機切斷電源時關閉電動調節閥。 兩種連鎖線路連接方式，分別用于斷電復位設備和電關設備，用戶可據具體情況自行取舍。（有防凍要求的場合可通過行程限位器將熱水閥位保持在要求的開度）。

2. The electric control valve is interlocked with the fan to ensure that the air valve is also closed when the fan power is cut off. The electric control valve can also realize linkage with the fan. When the fan is cut off, close the electric control valve. Two interlocking line connection modes are used for power-off reset equipment and power-off equipment, and users can choose between them according to specific conditions. (In case of antifreeze requirements, the hot water valve can be kept at the required opening through the travel limiter).

3、在需要制冷時，溫控器置于制冷模式，當傳感器測量的溫度達到或低于設定溫度時，溫控器給電動閥一個關閥信號，電動閥的關閥接點接通閥門關閉。如果測量溫度沒達到設定溫度，溫控器給電動閥一個開閥信號，電動閥開閥接點接通閥門打開。

3. When refrigeration is required, the temperature controller is placed in the refrigeration mode. When the temperature measured by the sensor reaches or is lower than the set temperature, the temperature controller sends a valve closing signal to the electric valve, and the valve closing contact of the electric valve is connected to the valve and closed. If the measured temperature does not reach the set temperature, the temperature controller will send an opening signal to the electric valve, and the valve opening contact of the electric valve will be connected to open the valve.

4、在需要制熱時，溫控器置于制熱模式，當傳感器測量的溫度達到或高于設定溫度時，溫控器給電動閥一個關閥信號，電動閥的關閥接點接通閥門關閉。如果測量溫度沒達到設定溫度，溫控器給電動閥一個開閥信號，電動閥開閥接點接通閥門打開。

4. When heating is required, the temperature controller is placed in the heating mode. When the temperature measured by the sensor reaches or exceeds the set temperature, the temperature controller sends a valve closing signal to the electric valve, and the valve closing contact of the electric valve is connected and the valve is closed. If the measured temperature does not reach the set temperature, the temperature controller will send an opening signal to the electric valve, and the valve opening contact of the electric valve will be connected to open the valve.

5、當過濾網堵塞時或當其超過規定值時，壓差開關給出的開關信號。當盤管溫度過低時，低溫防凍開關給出開關信號，風機停止運行，防止盤管凍裂。

5. When the filter screen is blocked or exceeds the specified value, the switch signal given by the differential pressure switch. When the temperature of the coil is too low, the low temperature antifreeze switch gives the switch signal, and the fan stops running to prevent the coil from freezing.