In a very simple setup a boiler provides heat to one heating circuit. If heating activated is on, the boiler maintains the selected flow temperature by regulating the burner and the heat pump.
Once the current flow temperature exceeds the selected flow temperature + temperature hysteresis off, the heating will stop until the current flow temperature drops below the selected flow temperature + temperature hysteresis on (which is typically a negative value).
Thus to activate the heating you will need to set heatingactivated to on and set an appropriate flowtemp. The latter should be derived from the heating temperature setting which can be set using the physical dial/control on the boiler. It should be considered as the maximum flow temperature. You can also use a lower flow temperature to maintain a constant room temperature once the initial heating is done.
<?php
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curl_exec($ch);
curl_close($ch);
?>