NCB 240/110H combi unit installed here, mostly the same protocol, but the starting bytes are f7 06 instead of f7 05. @htumanyan (Likely) CRC checksum calculation and seed remains the same.
I’m trying to figure out the hotbutton serial data to send, but don’t have a navilink to capture the data. It doesn’t respond to the hotbutton press/release commands above starting with 0xf7 0x05. It also doesn’t respond to the hotbutton commands with a 0xf7 0x06 prefix and a recalculated checksum.
Example Incoming Packet:
[15:02:04][I][Navien:211]: f7 06 50 0f 90 2a 45 00 0d 01 0a 06 0e 83 5a 33 2e 4d 46 9e 00 21 00 00 7b 43 00 00 5f 01 70 05 00 00 00 00 25 01 a7 04 9a 06 78 3c a4 50 00 00 36
There are still just two packets.
switch (serialBuffer[3]){
case 0x50:
PowerState.publish_state(serialBuffer[9]);
WaterFlow.publish_state(serialBuffer[18]/10.0*0.2642); // GPM
SysStatus.publish_state(serialBuffer[24]);
break;
case 0x0F:
ESP_LOGI("Navien", "%s", buffer);
HTSetpoint.publish_state(serialBuffer[13]/2.0);
DHWSetpoint.publish_state(serialBuffer[14]/2.0);
DHWOutlet.publish_state(serialBuffer[15]/2.0);
DHWInlet.publish_state(serialBuffer[16]/2.0);
HTTempSupply.publish_state(serialBuffer[17]/2.0);
HTTempReturn.publish_state(serialBuffer[18]/2.0);
gasUsageBytes.b1 = serialBuffer[22]; // low byte
gasUsageBytes.b2 = serialBuffer[23]; // high byte
GasUsage.publish_state(gasUsageBytes.us1);
GasTotal.publish_state(serialBuffer[24]/10.0);
break;
}