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HVAC Guru
HVAC Guru, HVAC TECH
Category: HVAC
Satisfied Customers: 14031
Experience:  15yrs in the HVAC industry with certificates and degrees.
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I am trying to set up my Nest with my old system JA: I'll

Customer Question

I am trying to set up my Nest with my old system
JA: I'll do all I can to help. Tell me a bit more about what's going on so we can help you best.
Customer: My old system has an O and a B wire and the new system has an O/B wire. I don't know where the O and B should go
JA: Anything else I can tell the HVAC Technician before I connect you two?
Customer: If I only have 1 W and 1 Y, should these go toW1 and Y1? I also don't have an E, HUM, DEHUM or W3 wires
JA: Good to know. The mechanics have tons of experience dealing with this sort of thing. How old is your transmission? I'm sending you to a secure page on JustAnswer so you can place the $5 fully refundable deposit now. While you're filling out that form, I'll tell the HVAC Technician about your situation and connect you two.
Submitted: 8 months ago.
Category: HVAC
Expert:  HVAC Guru replied 8 months ago.
Hello and thanks for using this service, if you have been waiting do not worry or get upset. I am Appliance Guru an extremely experienced tech on here and I try to get to as many customers as I can. I just picked up your question now. Please allow time for me to respond, sometimes I get the questions or responses late so please be patient as I have no control over the site issues. NOTE, I have nothing to do with your payment to the site and personally did not receive that money. The only way I am credited is when you use the STAR/VOTE RATING SYSTEM at the top of your page. Lastly when we are done please post to me that you would like me "GURU" credited before supply the rating so there is no confusion on the tech to be credited for the question. Thank you! ANSWER: If your old system used a separate o and b wire you may not be able to use the NEST some systems require a separate O and B wire to make them run. Can you see where the O and B terminals terminate in the unit?
Customer: replied 8 months ago.
I guess I do not understand the question
Expert:  HVAC Guru replied 8 months ago.
If you had a separate O and B wire to the old unit there is a good chance you can not use the NEST
Customer: replied 8 months ago.
So there is nothing I can do about this?
Expert:  HVAC Guru replied 8 months ago.
Depending on where your O and B wires go to the furnace or unit outside that will make the difference, can you check to see what terminals they connect to in the unit?
Customer: replied 8 months ago.
How would I do this?
Expert:  HVAC Guru replied 8 months ago.
You need to get into the furnace and check where the O and B wires land on the control board let me know what terminals they are going to
Customer: replied 8 months ago.
It they go to the Zone 1 T'stat. There are two connectors in this section. The first connector has a C, W, Y, R. W and Y are connected. The second has an R1, O, B, G. The R1, O and B are cnnected
Expert:  HVAC Guru replied 8 months ago.
Do you have a zoned system?
Customer: replied 8 months ago.
Yes two zones
Expert:  HVAC Guru replied 8 months ago.
Ok this is more complex to do I will see if another expert can help
Customer: replied 8 months ago.
Oh, thank you