Sensor for circulating pump

[Buppi77]

Hello everybody,
i'd like to start a circulanting pump when the heat pump starts to heating but i don't understand if there is a sensor that can give me this information.
Is there a sensor that can tell me when the compressor is on for heating?

[jwillemsen]

There is no specific sensor that tells you that, maybe the leaving water temperature can be helpful or install a energy meter before the altherma?

[Buppi77]

Thank you for your quick reply!
I've seen in the github raomin/ESPAltherma that this sensor is available at the serial port X10A (there is also a sensor thet tells you if the compressor is defrosting the HP)... but I would prefer to use your solution based on the integration with Daikin Cloud... I wonder why Daikin doesn't make these sensor available

[jwillemsen]

Daikin has sells an optional homehub to expose the data from the port but that is around 400 euro exclusive installation costs so it is very unlikely they will make all this data available for free through their cloud api.