[SOLVED] Homematic Number Values don't sync from openhab 2 to CCU2

Hi Community
The sync from ccu2 to OH2 works fine and without problems. I have Change a switch in OH2 the switch is also changed in CCU2 - Number Items / Variables are not working at all.
Now I calculated an temperature average in OH2 and want to sync this back to CCU2.
my item:

Number SVTagestemperatur "Durchschnittstemperatur 24h [%.1f °C]" (HM_Variables) {channel= "homematic:GATEWAY-EXTRAS-PI:PI:GWE00000000:1#Tagestemperatur"}

then I calculate the average.

SVTagestemperatur.postUpdate(WUG_Temperature.averageSince(now.minusMinutes(1440), "jdbc"))

this works fine, but with the next resync the value from ccu2 Shows up again.

Calculate average:
2018-06-27 16:51:19.589 [vent.ItemStateChangedEvent] - SVTagestemperatur changed from 25.11 to 18.40884131265685
Recalculate the average:
2018-06-27 16:51:23.213 [vent.ItemStateChangedEvent] - SVTagestemperatur changed from 18.40884131265685 to 18.40931011704348
Resync from CCU2:
2018-06-27 16:51:55.034 [vent.ItemStateChangedEvent] - SVTagestemperatur changed from 18.40931011704348 to 25.11

What is wrong - do I miss something

Thanks for your support.

Shouldn’t you be making a sendCommand rather than a postUpdate to the CCU2?

Thanks Tom,
yes this worked. I changed to

SVTagestemperatur.postUpdate(WUG_Temperature.averageSince(now.minusMinutes(1440), "jdbc"))
sendCommand(SVTagestemperatur, SVTagestemperatur.state to Decimal)

I will close the issue.