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Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 5648
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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I am trying to wire a nest thermostat to the ac unit in my

Customer Question

I am trying to wire a nest thermostat to the ac unit in my place. After following the directions from nest, the thermostat was only running the fan, ambient air. Any thoughts on this?
JA: Thanks. Can you give me any more details about your issue?
Customer: Yes, in the old thermostat I had a red-RC, brown-O, yellow-Y, green-G. There were also a white and blue that were unused wrapped up inside.
JA: OK got it. Last thing — HVAC Technicians generally expect a deposit of about $18 to help with your type of question (you only pay if satisfied). Now I'm going to take you to a page to place a secure deposit with JustAnswer. Don't worry, this chat is saved. After that, we will finish helping you.
Submitted: 6 months ago.
Category: HVAC
Customer: replied 6 months ago.
When I connected to the nest thermostat, I had yellow-Y1, green-G, brown-O/B, and red to Rc. I followed the rest of their directions. When the thermostat tried to start cooling, only the fan would start up. Would I need to connect the unused wires to one of the other terminals? my ac unit is is a HEIL EBX4800A, by the way.
Customer: replied 6 months ago.
The unused terminals were Y2, W1, W2/AUX, C, *, and RH
Expert:  Airheatman replied 6 months ago.
If the wires were not connected on old, they should not need to be on the Nest.Try moving the red to RH
Customer: replied 6 months ago.
I will try that later tonight. Are there any other possibilities I could try? For instance, in the old system, RC and RH were jumpered, as as Y and W. Nest says that no jumpers are needed in their setup, but, forums say that in some cases this is not the case.
Expert:  Airheatman replied 6 months ago.
There should not be a jumper needed.On old thermostat Y and W were jumped so compressor was energized in both heat and cool modes.On the Nest, it is not needed.

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