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[sumptersmoker]

I used the wiring diagram from Central boiler for the wiring of the second thermostat.. I have a forced air furnace with central air. The compressor fan keeps coming on ... what did I do wrong ?

[RSI]

You need to take the wire off the G terminal on the original thermostat, not just add the new wire. Just splice it to the wire going to the new thermostat.

[netwerx-r-us]

would you be kind enough to share that diagram? , that actually was going to be one of my next posts to ask for that  , thank you sir

[jbc]

Lets call your old thermostat "thermostat A"...New one added to your system "thermostat B"

On thermostat A look for the G marked terminal, it should have your A/C wire hooked to it....REMOVE the wire going to the G terminal on Thermostat A.....

Next take the wire that is running from thermostat B (W marked one) and attach that to the "now" empty terminal G on thermostat A....wa'la your done---you will have the reverse the 2 wires in the spring for the A/c to work....there's other ways you can do this--but this is the easiest way.

Basically, the G terminal on a thermostat is the fan activation wire----when you do not unhook the A/C wire from thermostat A when you hook up thermostat B to it---the thermostat B wire backfeeds the A/C system and turns it on.

I'm a picture dunce on this forum..sorry

[sumptersmoker]

I just took the orginal thermostat off the wall and the compressor just stopped. Im not sure I understand what is going on but im not a HVAC guy ...

[sumptersmoker]

So did I just trash my compressor for the last 2 weeks my boiler was running ?

[jbc]

ok here is a nice posting also...still dont have a pictures for ya' but the internet should be your friend.

http://outdoorwoodfurnaceinfo.com/forum/index.php?topic=1348.0

[RSI]

the G wire is for the fan. (Y is the compressor)
You need to remove the wire on thermostat A and leave it empty. Run the wire you took off the G terminal on thermostat A and run it to the W on thermostat B Then add a wire onto RH (leave original wire on this terminal too) of thermostat A and run it to RH on thermostat B.

Or you can just disconnect the wire from the Y terminal but then your AC won't work anymore.

[sumptersmoker]

the G wire is for the fan. (Y is the compressor)
You need to remove the wire on thermostat A and leave it empty. Run the wire you took off the G terminal on thermostat A and run it to the W on thermostat B Then add a wire onto RH (leave original wire on this terminal too) of thermostat A and run it to RH on thermostat B.

Or you can just disconnect the wire from the Y terminal but then your AC won't work anymore.

I just took the wire from G on the old stat and ran  it into the w on the new one.. do I still need to disconnect the yellow on the old one... ?

[tanner]

This is kinda what i had a ? about but im wona just use my old thermosat it has a off and cold and heat switch and when i turn the heat on my gas furnace kicks on i would like to un hook the gas furnace and make the fan come on with out my gas furnace trying to come on any ideas?

[RSI]

the G wire is for the fan. (Y is the compressor)
You need to remove the wire on thermostat A and leave it empty. Run the wire you took off the G terminal on thermostat A and run it to the W on thermostat B Then add a wire onto RH (leave original wire on this terminal too) of thermostat A and run it to RH on thermostat B.

Or you can just disconnect the wire from the Y terminal but then your AC won't work anymore.

I just took the wire from G on the old stat and ran  it into the w on the new one.. do I still need to disconnect the yellow on the old one... ?

You don't have any wires on the G terminal on the original thermostat and the compressor is still coming on?

[RSI]

This is kinda what i had a ? about but im wona just use my old thermosat it has a off and cold and heat switch and when i turn the heat on my gas furnace kicks on i would like to un hook the gas furnace and make the fan come on with out my gas furnace trying to come on any ideas?

If you want to just completely disable the gas and use the existing thermostat, all you have to do is take the W wire off and move the wire from the G terminal to the W.

[sumptersmoker]

I think I got it ... I just have to switch the wires back for cool air... Now do you think I did any harm to my compressor ?

[Jack72]

You need to take the wire off the G terminal on the original thermostat, not just add the new wire. Just splice it to the wire going to the new thermostat.

Hello RSI.   
I've been wondering about this      This may be a stupid question.  But I've always just shut the breaker off to the ac   And just turn back on in the summer is this a bad thing or just a easy way out      I haven't ran mine OWB in the summer yet so it's not a issue for me right now     Thanks for any input you can give


Thanks Jack. 

[lasor1]

You can put a diode on wire going to tstat to keep power from back feeding old tstat that would work too! Without changing anything but I like the relay deal it will keep them isolated from each other and I will probably change mine to relay in future but no problems here with diode inline