Replacing a Lennox thermostat Does W2 or Y2 go to the O/B terminal?

[clive_bob]

I have 7 wires coming from my Lennox thermostat.  There are only 6 terminals on my 3rd Gen Nest.  The manual says if I have a W2 or Y2 to insert in the O/B terminal.  I have both W2 and Y2.  My system is gas forced air.  Does W2 or Y2 go to O/B?

Thank you in advance!

Bob

[Patrick_Caezza]

@clive_bob 

Can you post a picture of the original thermostat's wiring here?

If the camera icon isn't present yet, you can use the imgur.com upload site and post the link it provides here.

[clive_bob]

I found my answer.  W2 is for a heat pump.  Y2 is for non-heat pump.  Thanks for your assistance.