Need help with Nest Gen3 thermostat wiring connections- NO HEAT

[Sami289]

Hi, I installed the thermostat few months ago and it worked fine for A/C needs. Today when I turn on heat, it started the A/C instead.
Old Thermostat didn't have Black (C) wire connected so I connected it in the furnace with right most white wire (which has marked C).
After reading online, I disconnected the orange wire (which I initially connected to Y terminal on Google Nest. After that heating did turn on but after a min i stated feeling a weird burning smell.
Coleman brand furnace is gas based ( no heat pump). Please see the attached pics of the furnace connections, old thermostat connections, and new google nest thermostat connections

Thanks in advance for your helpOld thermostat connectionsI connected black wire to top right with white wireA/C was working in this setup. When I disconnected orange wire, heating turned up and I feel a burning smell so I turned off the furnace

[Sami289]

Hi @Patrick_Caezza

any feedaback on this?

thanks

[Patrick_Caezza]

Did you run and connect the black wire to the C terminals?

[Sami289]

@Patrick_CaezzaYes I connected the black wire to the C terminal and that's how A/C was working fine. Now if I disconnect the "Orange" wire, the heating works ok as well

But not sure if A/C would work ok after disconnecting Orange wire

[Patrick_Caezza]

@Sami289 

When you set up the thermostat in the app, what wires did you tell it you had?

I'm referring to this screen.

[Sami289]

@Patrick_Caezza  If I remember I selected R, C, W/W1, G/G1