Replacing Honeywell BDR91 with Tado receiver.

[broonsbrew]

I'm new to this forum and I've been watching the threads hoping my BDR wiring would come up. But no luck yet. As you can see from the wiring photo, there are 2 Blue wires in the N terminal and a Brown wire in each of the L ones. Do I wire the 2 Blue wires together into the N terminal in the Tado receiver and the two Brown wires into the L terminal in the Tado as their installation suggests? To my mind that would mean the boiler is on all the time. I'm confused and hope someone has been here before. Heeeelp please.

 

[stem]

The Tado simply replaces the BDR no need to touch anything else. However, you haven't provided details of the Tado unit you want to connect. there are several variants and the wiring is not the same.

The two BDR L terminals are electrically connected together internally so are the same terminal anyway. A&B are the heating control wires

 

[broonsbrew]

Hi Stem. That was quick thank you. Enosed is the Tado unit I'm going to be using.

 

[broonsbrew]

So it looks like I can just wire the two Blue wires into terminal N and the two Brown wires into terminal L on the Tado receiver. The Black wire into Com and the Grey into N/O in the Tado.

 

[stem]

Sounds about right.

The wires in BDR A & B are the heating system control wires. BDR N & L are the permanent supply to the receiver and also to the boiler. So to replace the BDR with the Tado unit.

Both wires in BDR N = Tado N
Both wires in BDR L = Tado L [The two BDR L terminals are both connected to each other internally]
Wire in BDR A = Tado CH COM
Wire in BDR B = Tado CH NO

The Tado unit you have can provide control of CH and HW (heating a hot water cylinder). However, if you intend to replace the BDR with it, it will only control the CH. There are no hot water control wires at the BDR. If you have a combi boiler that only reqires CH control then it's of no concern.

 

[broonsbrew]

Thank you Stem that's fantastic. Going to do it now so will let you know latter

 

[broonsbrew]

Hi Stem. That all worked a treat. Thank you for your input. Fantastic