Can I reconnect the wires from my old Siemens receiver to the Tado receiver?

JJ24

I'm considering replacing my Siemens RDJ10RF Programmable Room Thermostat and Receiver with a Wireless Tado V3.

I have a Baxi Platinum Combi boiler, with the wiring from the boiler already connected to the Siemens receiver. I'm therefore wondering if I can avoid opening up the boiler and instead simply disconnect the wires from the Siemens and connect them to the Tado? If so, where do I put the two wires that are connected to points labelled L1 and LX?

Pics below of the receiver and page in the manual that highlights what L1 and LX mean. From the looks of it, it seems the wire currently in LX should go into CH NC on the Tado.

https://postimg.cc/gallery/HMgvDNW

policywonk

According to this guide: https://assets.new.siemens.com/siemens/assets/api/uuid:1fa84e757f41525a62bb60d08b65400267f8bb3e/rdj10rf-datasheet.pdf
...your existing stat has the following wiring.
* N is neutral
* L is live dedicated to the thermostat, no other purpose.
* Lx is the live to switch trigger from the boiler
* L1 is the Normally Open, or NO, return Live feed when the thermostat is calling for heat.
* Nx is the return Neutral.
Now if the electrician who fitted this was being careful, this is how it should transfer to a Tado wall wired stat:
* N to P1
* L to P2
* Lx to COM
* L1 to NO
* Nx to P1.
Don't forget to isolate power before you mess with this.