I had a contractor install duct work to my new addition and told him we would like to make it 2 zones (one controlling existing ducts and other controlling addition). He installed the EWC ST-2E zone control system. I have a trane propane furnace and a 3 ton central ac unit. It was also known that I had a NEST t-stat that I was hoping to use for both thermostats. Original thermostat is a Honeywell RTHL2410C1005 and could be used if needed as last resort to the more fancy NEST. I asked him if the NEST is compatible and he said it sure was and installed it at thermostat 1 location and removed my Honeywell. It seemed to work fine for a day or two after the contractor left and then no AC. My nest will say cooling, the fan kicks on in furnace but the AC unit outside does nothing. When i turn the heat on, all seems to work fine. I have not tried zone 2 yet at this time. The contractor hasn't returned any of my phone calls and I'm attempting to remedy the issue myself with the help of the community. We were hoping to have 2 zones, where each thermostat could be set to heat/cool and work seperately from each other. They fried my propane furnace control board during installation and had to replace that unit as well, which worried me that things may still be messed up.
Here are some pictures of the wiring job that the contractor did. Does this wiring look fine or is there something that needs changed? The 2 wire from my central air unit back to the furnace is shown connected in the top picture below to the 'C' terminal and 'Y' terminal on my furnace board. The remaining wires in top photo connect to the area labeled system in the EWC panel. The blue wire is just hanging loose next to system wires and is not connected as shown in photo but its connected on the furnace board at other end to the 'C' terminal.
New NEST thermostat, contractor installed
Origional Honeywell T-stat that was removed from t-stat 1 when NEST was installed.
Last edited by karpinator on Sat May 18, 2019 1:55 pm, edited 1 time in total.
