I've seen in all the posts that the "heat for 10 sec" issue has been reported multiple times. But this problem persists in the latest version 0.4.11 As it cost me a contactor, I searched a bit to find where this error came from. I changed this line (lin 367) in the program: if power == 0: by if ...

Look at this:
https://github.com/syrhus/domoticz-weekly-planning