1. E01: This code indicates a problem with the ignition system or with the gas supply. It is possible that the gas valve is not opening properly， the gas pressure is too low， or there is a problem with the ignition electrode or sensor.

2. E02: This code indicates a problem with the flame sensor or sensor wiring. It is possible that the sensor is dirty or damaged， or that the wiring is loose or damaged.

3. E03: This code indicates a problem with the fan or fan motor. It is possible that the fan blades are dirty or damaged， the motor is overheated， or there is a problem with the fan control circuitry.

4. E04: This code indicates an overheating problem in the boiler. It is possible that the water pressure is too high or the flow rate is too low， or there is a problem with the temperature sensor or thermostat.

5. E05: This code indicates a problem with the gas valve or gas pressure sensor. It is possible that the valve is not opening properly， the gas pressure is too low， or there is a problem with the sensor itself.

6. E06: This code indicates a problem with the condensate drainage system. It is possible that the drain pipe is blocked or there is a problem with the pump or sensor.

7. E07: This code indicates a problem with the circulating pump or pump motor. It is possible that the pump is dirty or has failed， or there is a problem with the motor or control circuitry.

8. E08: This code indicates a problem with the high limit switch or temperature sensor. It is possible that the switch is faulty or the sensor is reading incorrectly.

9. E09: This code indicates a problem with the low water pressure sensor or flow switch. It is possible that the sensor or switch is faulty or there is a blockage in the water flow.

10. E10: This code indicates a problem with the gas control valve or gas pressure regulator. It is possible that the valve or regulator is faulty or there is a problem with the control circuitry.