HM-CC-RT-DN Thermostats Unreachable after Upgrade


Hi I have seen similar issues on the Forum but can’t seem to get my Homematic HM-CC-RT-DN thermostats working properly in Homegear after upgrading recently. I am running the software on a RPI 2 with OPENHABIAN which is also updated to the latest version. I use Homegear as a bridge to OPENHAB2 also running on the same RPI. I am using the RPI BidCOS Dongle to communicate with the thermostats. All was working fine until upgrading the Homegear version to latest.

The thermostats work for about 10 minutes when starting HomeGear then go to UNREACHABLE. Logs attached (Log Level 4). I would be grateful for any assistance.

Many thanks in advance!

homegear.err (742 Bytes)
homegear.log (465.6 KB)


Hello @vhbevan,

sorry for the late reply. I’m not seeing any incoming packets in your log. What communication module are you using? There seems to be an error there.




Hi sathya,

I rebuilt the whole openhabian and homegear environment and now all is working well. I just have an issue with two homematic HM-Sec-SC-2 window sensors which I cannot pair or factory reset as the manual states they are already paired to my original hub , i.e. the initial homegear configuration. Can you offer any advice as to how I can achieve this in homegear as the devices aren’t paired anymore to homegear? Note I haven’t used AES originally and still don’t.




Hi @vhbevan,

For the HM-Sec-SC-2 AES is mandatory, so it had to be enabled. For the repairing to work, you need to know the original setting for centralAddress and rfKey for the pairing to work. After pairing the window sensors, I would factory reset them from Homegear and pair them again.