How to fix eWelink thermostat error code “E2”?

I recently purchased Splenssyy eWelink-compatible smart thermostat. The thermostat looks like it’s working, and its temperature readings show properly – but where it should read “heating”, it just says “E2”. What do? Problem Status (or error code) “E2” means “External sensor needed”. So either your external sensor (NTC thermistor) is not installed or it doesn’t […]