A friend of mine has a C4 system and recently purchased some used equipment, first 2 WT-100's and then an EC-100 in an attempt to get the thermostats working. So far his dealer hasn't had any luck so I thought I would try here. He has a small install HC-300, half dozen switches, etc. I know they were able to find Thermostat driver but not the EC-100. Does anyone have any ideas or input? The goal is to get the thermostat working, he isn't as interested in the extra functionality of the EC-100. thanks in advance