Full write up below.
Here’s how to keep alive with OH3.
Settings → Rules → Add a new rule with a 30 second cronjob.
Execute a script should be a “Run a Script” type using Rules DSL. This is the script.
actions.get("mqtt", "mqtt:broker:1e24481776").publishMQTT("R/a0f6fd5aa8b8/system/0/Serial", "");
logInfo("Solar", "CCGX MQTT Keep Alive Timer fired!!")
Change your broker ID in the first line accordingly. Watch your log and you’ll see it fire every 30 seconds.
Z.