Nest thermostat causes fan to start blowing IMMEDIATELY after setting to Heat mode

[stevefisher99]

I have forced hot air natural gas furnace, and separate outside A/c unit....I installed a new Nest thermostat (it has 6 terminals), plugged the 5 wires into their corresponding sockets  [G-G, R-R, W-W, Y-Y, and Blue wire to C terminal,  the OB terminal is not used].......  Nest controls the A/c perfectly.......however when I set the mode to heat, the air blows immediately out of the registers, there is no delay while the furnace pre-heats.......Can someone look at my picture, and tell me if this setup [forced hot air natural gas furnace, and separate outside A/c unit] can be controlled with this model Nest?  I thought it a little odd the C power terminal is sharing a blue and red wire, and the Y terminal is sharing a yellow and white wire?  I'm guessing one is the furnace and the other the A/C?

[Markjosephp]

Hello stevefisher99,

I'm sorry for the late reply and thanks for sharing the picture of your system control board. Let's see what's going on.

Based on the wiring configuration and how you labeled these wires to your Nest thermostat, it is correct. Make sure that fan schedules and auto-learning schedules are off or disabled, so your Nest thermostat won't activate your fan when calling for heat or cooling. Here's your guide to your Nest thermostat settings.

Let me know if that helps.

Thanks,

Mark

[Markjosephp]

Hi there,

I'm checking back in. Were you able to do the steps above? I'd be glad to hear from you — I'd like to make sure everything is working.

Best regards,

Mark

[aatienza]

Hey there,

Just checking in to make sure that you've seen our responses. Please let me know if you have other questions or concerns as I will be locking this in 24 hours if I won't hear back from you again. Feel free to start a new thread and we'll be happy to help.
 

Thanks,

Archie