Honeywell e04是什麼意思

Honeywell E04 is an error code that indicates a problem with the heating system. Specifically, it means that the system is not reaching the desired temperature. This could be due to a variety of factors, such as a malfunctioning thermostat, a problem with the heating elements, or a clogged filter. If you are experiencing this error code, it is important to have a professional HVAC technician diagnose the issue and provide the necessary repairs.