I had been reading a lot about installing the Venstar 7-day thermostat. One question remains, will I be able to install this without running a "Common" wire. Here is a photo of my existing thermostat and the wires connecting it to my heating/cooling plant:

 

 

Common is the the reference point for the other wires and is required. What kind of system do you have? If you don't have enough wires for your install pull the wires out of the wall a bit because it is common to wrap unused wires around the cable.

 

As another note if you are just replacing the existing thermostat and keeping the existing central air then the terminals are the same on the Venstar.

. . . As another note if you are just replacing the existing thermostat and keeping the existing central air then the terminals are the same on the Venstar.

 

I am not sure what you mean. with my current setup do I need any additional wires or will I be abel to install the Venstar with the existing wires?

I found the installers manual for that thermostat.

You may want to look at it.

 

I am not a HVAC expert but the C terminal on your present thermostat maybe the Common you need and the photo shows a wire on it.

 

You could maybe look at the HVAC unit and see what is connected to its terminals.

The first link is the Carrier and the second is a Bryant. I suspect they also used it in their installations.

 

http://www.managemylife.com/mmh/owner_m ... s-L0210344

 

Adobe can save the manual if you click on the small disk icon on the display.

 

http://www.gogeisel.com/geiselonline/su ... nstall.pdf

I am not sure what you mean. with my current setup do I need any additional wires or will I be abel to install the Venstar with the existing wires?

 

From the picture it appears you have a Common wire but you are asking can you install the Venstar without a Common. I'm pretty sure the Venstar requires 5 wires. If you have 5 wires then you should be okay. If not Smarhome has an Add A Wire kit that I think converts a 4 wire run to a 5 wire run. There is a good guy on the Smarthome forum that knows all about HVAC and Venstar. You should post the question on the Smarthome forum under "Thermostats and HVAC Control".

Thanks guys, I am ok with electricity but HVAC is something else

The 5 wires you have should work. R and C for the +24VAC, one each for fan, heat, and cool.

 

The guide shows wire #6 for 2-stage heating, but then you would already have W2 connected.

http://www.smarthome.com/manuals/30412a_install.pdf

 

Rand

Thanks! One last question, does the ISY synchronize the time on the thermometer? I assume so but I wanted to check, this is one of the issues I'm experiencing with my current thermometers.

No, there is no method for the ISY to set the time.

 

Thanks! One last question, does the ISY synchronize the time on the thermometer? I assume so but I wanted to check, this is one of the issues I'm experiencing with my current thermometers.