O Baik

You are right about the registered controller and I was able to see the slave HC300 in the Monitoring tab. Thanks for clarification and explanation. Now things became very clear to me.

Thanks again. One more question to clarify: Does physical replacement of a slave controller requires reprogramming if the project already had the slave controller properly in.

Thanks for your reply. If I just to switch the power supply of the dead HC 300 by newer one, still my dealer has to add?

I am a newbie in this C4 world. I have HC 800 and 300. Recently, I found my HC 300's power and other lights were gone except the very faint, red light on the wifi indicator. When I looked at the registered controller on my Composer HE, it was only HC 800. My dealer told me that HC 300 is a slave controller. I am planning to replace the HC 300 with the used one I purchased on ebay. In this case, do I have to have the newer HC 300 reprogrammed? To avoid the reprogramming, should I replace the power supply unit only? Thanks, OB