Any help would be appreciated as I am completely stumped. I am trying to connect two RC1000 HAI thermostats to an EWC NCM300 zone panel. I have connected the Zone 1 thermostat and it works fine. The Zone 2 thermostat also appears fine but when it calls for cool or fan the HCAC system is not activated. I have confirmed that there is 24VAC at the R and C at the thermostat. Thus it doesn't appear to be a power issue at the thermostat. I have also confirmed hat if i short G to R at the thermostat the fan goes on. Thus it doesn't appear to be a wiring problem or problem with the zone panel. I also confirmed that although a call is indicated (and there is a click too) there is not 24VAC between the Y/G and C terminals at the panel. Lastly, i have changed the Z1 and 2 thermostats and they both work fine while on Z1 so it would seem it isn't the thermostat either. So, it seems that for some reason the thermostat is not passing the voltage to the terminals (Y or G) when there is a call. Any ideas? Any help would be greatly appreciated!
HVAC Help!
- Thread starter oramos
- Start date
It sounds like the transformer on zone 2 is marginal as far as being able to supply enough power to drive both the thermostat and the fan relay. When you short G to R, does the display on the thermostat dim noticably? The other possibility is that the fan relay has a short in its windings and is drawing more current than it is supposed to. If you can get at it, you might want to check the fan relay's coil. If it looks burned or discolored, or if it smells, it's on its way to failure and you should get it replaced.
Thx. I tried that but it still doesn't seem to be working. I do have a common btw. Do you think the power kit will do it?
As tot he fan coil, I do not have access.
Thx for the suggestions. Appreciate it.
Steve
Senior Member
You have a common in the wire bundle and its at the thermostat but just not hooked up? If that is a 'hot' common then you should be able to hook it up to the stat and solve the problem.
