Hello.
I would like to know if it’s possible to force the domestic hot water (DHW or ECS) to activate with ESPaltherma?
The goal is to use the surplus solar energy produced. Has anyone succeeded in doing this?
Even with another system?
Thanks, Cédric
It is my understanding that the X10A port on an Daikin Altherma 3 gives useful serial interface, but is READ ONLY. Some projects use the smart grid connections to control the pump via a relay.
Personally, I’m using the cloud-based Onecta integration and after setting it up (not obvious to register), the integration works very well.
Full local control needs the Daikin gateway which connects to the Madoka/ MMI serial bus and LAN.
The latest Altherma 4 allegedly has ModBus on the main PCB, but not the v3.
If this helps, 
this post!
Hello James,
That’s great, it already helps me a lot.
Are you using Onecta with the Daikin gateway or with ESP on port X10?
Thanks
Cedric
I bought a “packaged ESP32” called a Faikout to connect to the Altherma X10, but after finding the port was read-only, I just use the cloud integration with Onecta for control and useful sensors.
I’ve got the JST connectors, ESP32, and several firmware options - just never bothered installing them (yet!).
The HA Onecta logging is so good, it seems better than my installer gets from Daikin telemetry as it proved the root-cause of AH-00 errors (legionella purge cycle never completed due to a poor temp sensor placement on the cylinder - never passed 60C).
Ok thanks i will try with onecta.
Cedric