Energy-saving wall-mounted boilers are popular home heating systems due to their low energy consumption and compact design. However， like any other electronic device， these boilers may sometimes malfunction， causing inconvenience and discomfort to homeowners. In this article， we will discuss some of the common error codes that may appear on an energy-saving wall-mounted boiler and their possible causes.

Error code E1: This error code may appear on the boiler's display， indicating a problem with the flow sensor or the wiring connecting the flow sensor to the control board. The flow sensor is responsible for detecting the flow of water through the boiler， and if it malfunctions， the boiler may not start or stop unexpectedly. To troubleshoot this issue， check the wiring and connections between the flow sensor and the control board. If the problem persists， call a technician to replace the flow sensor.

Error code E2: This error code may indicate a problem with the pressure switch or the wiring connecting it to the control board. The pressure switch is responsible for monitoring the water pressure inside the boiler and shutting down the system if it exceeds a certain limit. If the pressure switch malfunctions or the wiring is faulty， the boiler may not function properly or shut down unexpectedly. To troubleshoot this issue， check the wiring and connections between the pressure switch and the control board. If the problem persists， call a technician to replace the pressure switch.

Error code E9: This error code may indicate a problem with the ignition or the gas supply. The ignition is responsible for lighting the gas burner inside the boiler， and if it malfunctions， the boiler may not start or produce heat. Additionally， if there is a problem with the gas supply， such as low pressure or a gas leak， the boiler may not function properly or pose a safety hazard. To troubleshoot this issue， check the gas supply and the ignition system. If the problem persists， call a technician to replace the faulty components.

In conclusion， energy-saving wall-mounted boilers may experience various malfunctions， but most of them can be easily fixed by a professional technician. Homeowners should always keep their boilers well-maintained， regularly serviced， and follow the manufacturer's instructions to avoid future problems.