Replacing Honeywell BDR91 receiver with Tado Wired Smart Thermostat

[Giffone]

Hello folks,

I've been looking at this forum and other websites to get some help on the installation of the tado° Wired Smart Thermostat. I'm looking to use the new thermostat just as a on off switch for the central heating.

The BDR91 has been installed, by the previous owner, in combination with a combi boiler thermostat (which at the moment I don't need to replace). Just wanted to check with all of you the correct wiring before proceeding and potentially cause any unwanted damage.
The BRD is set up so that the additional live port is linked with the A port and the B port is just the switch live (230v) for the boiler.

Would it just be the case of connecting:

BRD91 A (which in this case would be the L wire) to TADO's COM
BRD91 B to TADO's NO

The bridge would be removed and the remaining neutral parked. I've attached some photos of the current setup and the tado thermostat.

Thanks a lot for the help!

 

[flameport]

Yes.
Use one of the parking P terminals for the neutral.

All it does is connect black and brown together when heat is required.

 

[Giffone]

Awesome, thanks a lot!

 

[stem]

The BDR91 has been installed, by the previous owner, in combination with a combi boiler thermostat (which at the moment I don't need to replace).

That's unusual, you have two room thermostats connected to one combi boiler? Normally I there would be just the one wireless thermostat that communicates with the BDR91 which switches the boiler on and off as required.

Where there are two thermostats they are usually for controlling two separate heating zones (i.e. upstairs and downstairs) but then, each of the two separate thermostats would be wired a motorised valve not the combi.

Having said that, as per @flameport what you describe is correct for replacing the BDR91 and wireless thermostat that it's paired with.