Complicated setup clarification help, please

[Wazzzo]

I am looking for help to check to see if our Nest Learning Thermostat 3rd gen is wired correctly. It's a challenging system though.

Single fuel house (electric). EHC Fusion e10 boiler that heats radiators and water.

Images including Fusion e10 Wiring diagram here https://photos.app.goo.gl/aVakTeNcCAGfUHTs7.

The system has 2 identical valves, both 3 way. I believe this suggests zoned heating but we only have one thermostat (original replaced with Nest). I believe a single valve suggest Y-Plan but searches suggest the addition valve complicates matters. Gemini live keeps suggesting having the Nest base station Live wire going from L to 2 to 5 (as is currently wired) isn't correct in this situation but eventually gives up and suggests I need a professional assessment.

At the thermostat end there is standard 3 core wire with the live connected to T2 and Neutral T1. Earth isn't used.

I have the orginal base unit with it's wiring diagram (see photos) but don't know what coloured wires were originally connected to what connection.

I have started to contact local Nest Pros but struggling to find someone confident enough to comment.

Any thoughts welcome.

Thank you

[EduardoN]

Hi @Wazzzo,

Thank you very much for sharing this information in this community! Regarding the issue with the connection of your Nest Learning Thermostat (3rd gen), where you want to know the correct way to make the connection, you have a connection with different wires and even consulted Gemini. After further verifying the photos you shared with us, it would be most advisable to contact a technician who can check the type of connection you have in more detail and make the necessary changes.

Keep me posted.

Best regards,

Eduardo