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+# JSON Commands
+
+Information is exchanged between the ESP32 and remote clients using JSON string formatting.  
+Only actual changes are transmitted to minimise traffic.  
+However, whenever a new client attaches to the ESP32, every client receives the full set of information.  
+i.e. every time a client connects, they will always get the complete status of the heater, then only changes to the values.
+
+The table below documents the JSON names sent between the ESP32 and Bluetooth or WiFi clients.  
+Some commands are bi-directional, others are simply command directives (to ESP32), or status reporting (from ESP32).
+
+Certain commands are used to alter the non volatile settings stored by the controller. eg Fuel mixture, timers.  
+**These must be followed up with a NVSave command.**
+
 | **Name** | **Value Type** | **Typical Values** | **Direction** | **Require NVsave** |
 | ------ | ------ | ------ | ------ | :------: |
 | BluewireStat| string | "OEM" _or_ "BTC" + ",Htr" _(if present)_ | From ESP | n/a |