Upgrading from nest 1st generation thermostat to 3rd generation wiring questions

[Enamir]

Hi, so my 1st generation thermostat died on me with odd issues that started 2 weeks ago and was not expecting it as it worked well with my hot water electric boiler which heats radiators.

i really believed that the same wiring would be recognized but to my surprise the 3rd generation thermostat had detected more wires than I have . 

ill attach pictures of 1st generation wiring and 3rd for you to understand. 

so can someone experienced explain why my wiring was detected in such a way even though I only have 4 wires (two from electric boiler & two from ac power 24v)

observe that in some cases some wires were completely ignored in 3rd gen

your help is appreciated 

1st generation wiring setup3rd generation wiring detection !

[Patrick_Caezza]

@Enamir 

What physical wires are connected to what on the 3rd Gen? Post a picture of the wiring of each if you can

[Enamir]

Hey Pat, thanks for reacting to my post. So the wiring in the new is identical to the way I wired the first thermostat, here are photos showing the old and new…

i tried uploading photos but it doesn’t seem to be possible in replies 😞 

so I’m wiring the new device’s base exactly the same way the original base of 1st generation was wired.