1. According to general conditions, two temperature sensors should be connected to thermocouples; two power cords should be connected to 220V power supply.
2. If the purpose of the 4 main lines is determined, only 6 connectors can be connected.
3. Measure the condition of 6 joints with the resistance file of a multimeter, 3 groups of heating coils or 2 groups of heating coils + a set of thermocouples.
4. The heating terminals should be connected in parallel