Swapping Honeywell BDR91 Receiver with Tado Wireless Receiver

[pkk11]

Hi folks, have been a stalker of the forum for a while during my DIY journey, but I stumbled upon an issue which I couldn't find suitable answers for in my specific case

I have a BDR91 receiver and I want to swap for a Tado V3+ wired system. Problem is that I'm unsure which wires go where. In the previous threads that I've seen, the wiring was all different unfortunately.
Boiler is Ideal Vogue C32.

My thinking is as follows about A and B, but not sure about the N and L
BDR91 A - Tado COM
BDR91 B - Tado NO


Really appreciate the help! Pictures of both are attached.

 

[RandomGrinch]

The Tado wired unit is battery operated. It doesn't require a connection to N, or L.
You can safely park them in the parking terminals - Say, L in P1 and N in P3.

The blue wire in your BDR91 terminal B, should be oversleeved in brown to denote it as a switched live.

When wiring up, isolate the power, and don't mix up the cables!

 

[CBW]

You’re correct, and would likely need to place L and N in separate terminal connections. Edit, forgot about the Park terminals!

 

[pkk11]

Amazing, thank you both.

So to confirm, wiring would be as follows:

BDR91 A - Tado COM
BDR91 B - Tado NO
BDR91 L - Tado P1
BDR91 N - Tado P3

 

[CBW]

Amazing, thank you both.

So to confirm, wiring would be as follows:

BDR91 A - Tado COM
BDR91 B - Tado NO
BDR91 L - Tado P1
BDR91 N - Tado P3

Yes.

 

[pkk11]

Reporting back progress, connected as above, however, the bloody relay doesn't seem to be working - Despite having the tado thermostat in the off position, the Ideal boiler is not turning off :/ it's constantly in the on position - I checked the connections and it's all looking fine
any ideas what might have gone wrong?

And thanks again for the help

 

[RandomGrinch]

the bloody relay doesn't seem to be working -

It should perform in exactly the same way as the BDR91.
Can you show us a picture of your wiring?

 

[pkk11]

Thanks @RandomGrinch! Pic is attached

 

[CBW]

Wiring appears ok. Wonder if it’s the L in parking? Do you have a terminal strip block or Wago to place the L in for now?

 

[pkk11]

Just put the L in a block and tried again, same issue unfortunately, boiler is still only in the On position.
Tried removing the faceplate (not sure if right term) of the tado and turning on the boiler and the correct behaviour is observed, where boiler in Off, not sure if useful info.

Thanks!

 

[CBW]

What do you mean by removed it? As I’m off the wall or wires disconnected?

 

[pkk11]

No no, I mean, have the connectors connected, but removed the brains of the tado ( I did it as I was worried in case something was shorted and was causing to be on all the time.

 

[RandomGrinch]

Tried removing the faceplate (not sure if right term) of the tado and turning on the boiler and the correct behaviour is observed, where boiler in Off, not sure if useful info.

Yes, that is useful, it tells us that the relay in the Tado is behaving incorrectly - either through some unknown setting, a sticky relay, or a fault.
I think from your description, you're telling us that the heating remains on, whether the heating is turned on, or off?
If so, can you remove the batteries completely and give the Tado a couple of gentle taps on its back with something like the handle of a screwdriver!
keep the batteries out for a while before replacing them and starting up the system.

That should hopefully free-up a sticky relay.

Are you using good quality alkaline batteries?

 

[pkk11]

I think from your description, you're telling us that the heating remains on, whether the heating is turned on, or off?

Correct

Batteries are the IKEA rechargeable ones 750mah, just took them out of the charger. Will buy some alkaline ones tomorrow to see if it fixes it.

In the meantime, just took them out, tried to tap it and left the batteries out for a bit, to no avail.

 

[RandomGrinch]

In the meantime, just took them out, tried to tap it and left the batteries out for a bit, to no avail

I'm afraid it sounds like a sticky relay to me. If you're lucky it may cure itself.
Otherwise it could be a call back to Tado.

There seem to be a couple of threads around with similar stories, on the Tado forums...

My heating is always on!

I've come from a nest system. I've got an s plan system, with two 2 port valves. One for Hot water and one for heating.

community.tado.com

heating does not turn off defective relays or software problem ?

Hi, I have my Tado thermostat for a bit over 2 years now, and the heating does not turn off anymore.

community.tado.com

My last suggestion (and least likely) for now - one of the posts above, mentioned settings related to Tado TRV's - during the setup process, have you inadvertently linked to a non-existent TRV?
Clutching at straws now!

I'm sorry this journey hasn't been the most straightforward.