I have a Siedle CA 812 running from a Siedle TR 603-0 transformer, together with standard indoor units. The problem is that the indoor units are too far from the front door, so I’d like to install a Nuki Opener on the inside of the front door.
I tested a setup using the Siedle transformer, a Shelly Plus 1 relay, and the Nuki Opener:
- Transformer port C → Lock
- Transformer port B → Shelly port I
- Shelly port O → Lock
- Nuki Opener Blue/Purple → Shelly SW/L
This worked perfectly — I can open the lock with either the Nuki Opener or the Shelly.
However, when I tried adding this to the existing setup (where ports C and B are already connected to the outdoor unit), the buzzer stays constantly on.
How can I solve this? My suspicion is that the Shelly needs to be added after the intercom, so that it acts as a relay for the whole system. That is, between the intercom and lock place the shelly and have the intercom and Nuki Opener act as a switch to trigger the Shelly.
Or can I solve by buying a second Siedle transformer? Unfortunately, the are not cheap…a