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[sumptersmoker]

do you think I did any harm to my compressor

[RSI]

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 ?

I am still confused here what is exactly happening. If you leave the G terminal empty on the main thermostat you should be able to leave the Y connected and the compressor should not run.

I don't know if it would have damaged the compressor. I don't see why it would have though, was probably just wasting a lot of power and wood.

[yoderheating]

If you are using a two thermostat system the only way for the compressor to come on is if its back feeding power to the old thermostat. A simple relay will fix that and you will not have to change wires around.

[sumptersmoker]

If someone has a diagram on the simple relay set up Im sure I could get the job done...lol Im just not a elect.

thanks for everyones help

[SperleFarms]

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

Why not just trip the main A/C breaker for the winter months and leave the thermostat wiring alone?  This way the system operates as it should, and there’s no need to flip flop thermostat wires every spring and fall.   

[RSI]

If someone has a diagram on the simple relay set up Im sure I could get the job done...lol Im just not a elect.

thanks for everyones help

I just drew up a really crude diagram. Did you try is like this?

[RSI]

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

Why not just trip the main A/C breaker for the winter months and leave the thermostat wiring alone?  This way the system operates as it should, and there’s no need to flip flop thermostat wires every spring and fall.   

If you just leave the G terminal on the original thermostat empty then you don't need to do anything, not even turn off breaker. If you do want to run the fan manually you can just turn up the temp on the second thermostat.

[Scott7m]

Can't we just place a diode in the yellow wire going to the outdoor unit? 

I always flip breakers on ones that backrest but have one now where customer has breakers all under his home

[RSI]

If you use a diode it will convert the power to DC and may or may not damage something on the furnace controls.

Anyway, if you do the diode, it would need to be on the G terminal of the original thermostat and go to the two spliced together wires. All that would do is allow you to keep the fan switch operational.

[Scott7m]

If you use a diode it will convert the power to DC and may or may not damage something on the furnace controls.

Anyway, if you do the diode, it would need to be on the G terminal of the original thermostat and go to the two spliced together wires. All that would do is allow you to keep the fan switch operational.


 your the electrical Guru, that stuff confuses me.  Like for example right now this customer can't turn his breaker off, wants his exsisting stat to work as it always has.  But the outdoor unit comes on with the blower, where would I put this relay?  What wire? 

I have seen this happen before but it was always convieinet for the customer to simply turn off the outside unit.  That's not the case this time

[RSI]

If you use a diode it will convert the power to DC and may or may not damage something on the furnace controls.

Anyway, if you do the diode, it would need to be on the G terminal of the original thermostat and go to the two spliced together wires. All that would do is allow you to keep the fan switch operational.


 your the electrical Guru, that stuff confuses me.  Like for example right now this customer can't turn his breaker off, wants his exsisting stat to work as it always has.  But the outdoor unit comes on with the blower, where would I put this relay?  What wire? 

I have seen this happen before but it was always convieinet for the customer to simply turn off the outside unit.  That's not the case this time

Did you wire it like the above pic?

[RSI]

If someone has a diagram on the simple relay set up Im sure I could get the job done...lol Im just not a elect.

thanks for everyones help

I just drew up a really crude diagram. Did you try is like this?

I forgot to mention before that the C wire to the new thermostat is only needed if the new thermostat doesn't use batteries.

[Scott7m]

No, w went to the g screw, didn't splice em together

[RSI]

If you just remove them and splice together the compressor shouldn't run when it isn't supposed to.

[Scott7m]

If you just remove them and splice together the compressor shouldn't run when it isn't supposed to.

What's the downside of doing this?

Does old stat still work the same as always