This command is used to change the device primary operational mode. Possible choices are heating (default for the device) and cooling. Switching from heating to cooling mode is required, when during the summer, cold water flow through the radiator. At the cold radiator water period end, switch to heating mode is required. Note that for both modes device functionalities open window detection and internal temperature control algorithm are available. The command data is described in Table 30. The keep-alive in the response is omitted for clarity.