我进行换热器设计时出现这种情况是什么回事啊急求

1107004525

**  ERROR
      TEMPERATURE CROSSOVER DETECTED
      RE-CALCULATING WITH MINIMUM APPROACH TEMP. SPEC


->Generating block results ...

    Block: H1       Model: HEATX
  **  ERROR WHILE GENERATING RESULTS FOR UNIT OPERATIONS BLOCK: "H1" (MODEL:
      "HEATX")
      TEMPERATURE CROSSOVER DETECTED
      RE-CALCULATING WITH MINIMUM APPROACH TEMP. SPEC
急求大家的帮助啊