Mein erster Versuch war doch richtig.
Also wieder zurück - aus den && ein || machen.
Ich hab die Zeile noch verändert:
else if ((temp2 > temp1 + hysterese / 2 || temp2 < temp1 - hysterese / 2) && sendMerker==true)Dann kommt sowas raus:
12:44:28.487 -> Sıcaklik=24.69 C
12:44:28.487 -> Sıcaklik=26.31 C
12:44:29.813 -> Sıcaklik=24.75 C
12:44:29.813 -> Sıcaklik=26.63 C
12:44:31.138 -> Pumpe an bei T1: 24.81 T2: 26.87
12:44:31.138 -> Sıcaklik=24.81 C
12:44:31.138 -> Sıcaklik=26.88 C
12:44:32.465 -> Sıcaklik=24.88 C
12:44:32.465 -> Sıcaklik=27.06 C
12:44:33.757 -> Sıcaklik=24.94 C
12:44:33.757 -> Sıcaklik=27.25 C
12:44:35.084 -> Sıcaklik=25.00 C
12:44:35.084 -> Sıcaklik=27.06 C
12:44:36.411 -> Setze Merker zurück
12:44:36.411 -> Sıcaklik=25.00 C
12:44:36.411 -> Sıcaklik=26.75 C
12:44:37.739 -> Sıcaklik=25.00 C
12:44:37.739 -> Sıcaklik=26.56 C