Take the 2-minute tour ×
Home Improvement Stack Exchange is a question and answer site for contractors and serious DIYers. It's 100% free, no registration required.

I am trying to replace my existing thermostat.

My old thermostat has:

Rh, W (coming from the heating unit).

Rc, Y, G (coming from the AC unit).

On the Venstar T5800, I can map as follows:

Rh+Rc -> R

W -> W

Y -> Y

G -> G

Now I need to add a common wire. HVAC tech tried to put a jumper between R and C. Venstar started up, the screen went on, but then the moment the AC turned on,the unit shut itself off. Is this a problem with the thermostat or with the way the HVAC guy set it up?

I bought an ELK 24V AC dedicated supply/transformer. Now I have two wires coming off it. It is running to my thermostat. How do I connect them? Does one wire from the supply/transformer go in to C and the other in to R, in addition to the Rc and Rh wires already in the R?

i.e. the following:

ACSupply1 -> C

Rh+Rc+ACSupply2 -> R

W -> W

Y -> Y

G -> G

Or would this not be recommended?

Any help with this would be very much appreciated. As you can see, I definitely need it.

share|improve this question
    
the answer on this question might help. –  Tester101 Jul 5 '13 at 16:51
    
The power supply trick is a hack, not a proper wiring technique. –  Tester101 Jul 5 '13 at 16:54

1 Answer 1

enter image description here

The picture below you would pull the green wire off of Green at both the stat and furnace and move it to C/Common, then you jumper Yellow to Green at the furnace.

share|improve this answer

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.