Tado + Remeha Avanta Plus 28c: Wiring question

miyo

Hi,

I have just purchased the wireless start kit (eu version) and need some confirmation regarding the wiring to a Rehema Avanta Plus 28c (OpenTherm compatible).

The boiler is currently connected to a Nest heatlink. The Nest is only connected via three wires; blue (N), brown (L) and black (3).

On the boiler side these wires go into block X2 as shown above.

The Tado installation guide suggests to locate block X9 and install the grey and black wires only into 7 and 8 respectively. The Tado install guide says to remove the jumper between 7 & 8, but there is no mention of what to do with the other existing wires.

This is how it looks with the Nest in place.

I did attempt to wire up the Tado receiver. I disconnected all the Nest wires from X2, but left the jumper between 3 & 4 as shown in the first picture above. I then connected the Tado wiring to block X9, with grey going into 8, black going into 7 (removing the jumper). I left the rest of the wiring in X9 untouched.

With this setup, the Tado receiver connected to the bridge successfully (I also noticed the firmware version was upgraded after a few minutes). The receiver had a solid white LED for “power” and “WiFi”. I then set the heating to high via the Tado app, which showed the room “heating to 24”, and the heating LED on the receiver was slowly pulsing bright, but the boiler never fired up. Hot water was still working on demand. I suspect the wiring is not quite right somewhere. I have now removed the Tado receiver and reinstalled the Nest, putting all the wiring back as shown above, and all is working as before.

Does anyone else have this boiler and can advise please?

The install guide for this boiler is here (terminals are explained from Page 21 onwards) https://www.dhsspares.co.uk/userfiles/boiler_manuals/REH005.pdf

Thank you

johnnyp78

look at p23 in your manual. Remove all the existing wires apart from black and grey in 7 and 8. They connect to + and - on the wireless receiver (doesn’t matter which way round). Sounds like you’ve already wired in the power so leave that as it is.

Make sure the wireless receiver is set for Opentherm (look at section 6). I would also download the Tado pro app to make doubly sure. https://cdn.brandfolder.io/607DGEMS/as/j4mjvsgpjtghjkm57fkx5q7h/104204-DIGITAL-WRB01IB01-INSTALLER_MANUAL-TA-EN-00-V3.pdf

miyo

Hi. Thanks for your response and apologies for taking so long to reply. At the same time as @johnnyp78 answered, I got a response from Tado, who told me

"You will need to remove the wires in terminals 1, 4, and 5. The bridge between 3 and 4 must stay, but you need a second bridge between 1-4. The tado° Wireless Receiver must be connected to 7 and 8, the order of the wires does not matter."

I tried this first, before trying the above answer, and it all worked, so left it there. Hope this helps someone else in future.

Shmalenyuk1111

Hi, I have also got Remeha boiler and want to install Tado. Could you advise how you eventually wired the receiver to take advantage of OpenTherm and boiler modulation?

miyo

Here are the two blocks and how they looked when I was finished and everything was working. I believe this setup is specific to my model listed in my original post. Make sure you have the exact same boiler if copying this wiring.

https://1drv.ms/i/s!AnU8OU7NvpdMyR-MFkvanyq0nT3c
https://1drv.ms/i/s!AnU8OU7NvpdMyR5b2QTRbYWSxUzE

I believe the blue&black wires in 1&2 on block X9 (which is the longer of the two blocks) is the outdoor temperature sensor, which is an optional extra on my boiler so you may not have these.

Shmalenyuk1111

Hi! Many thanks for the photos! My Boiler is Avanta Plus 35C and I believe the wiring is the same as it’s in the same boiler group. Have you got any photo of wiring a Tado receiver? I wonder why only two wires go into 7&8? Are they going to L&N on Tado receiver?

miyo

Hey. See this link https://1drv.ms/i/s!AnU8OU7NvpdMySDCL9rHaEhqcfNT

Only pay attention to the wires on the right (black and grey) as these correspond to the Tado wires going into block X9.

The wires on the left are for power to the Tado receiver. My Nest that I replaced was conveniently provided power from the boiler, so I tried to copy the wiring. This would avoid me needing a separate mains plug for just the Tado receiver. However with the various jumpers used on block X1 I never worked out how to wire in the power, so just used the 3-pin plug that came in the box with the Tado.

Shmalenyuk1111

Ah I see now, your receiver is different to mine. Looks like Tado supply two different receiver units depending where you based. I am from the UK and here they supply receivers without those Analog/Digital slots.

Seems like this confusion came up in forums and people complained why Tado secretly supply different receivers (BR02 and BP02).

I wonder what happens if connect two wires to 7&8 slots at the boiler and CHCOM&CHNO at Tado receiver. Is it still gong to work and Modulate the boiler? Guess, I’d have to chase Tado support.

johnnyp78

Tado doesn’t ‘secretly supply’ different wireless receivers- you’ve bought the wrong model. If you want to use a digital connection on a combi you either need the eu wireless receiver or a smart thermostat.

Shmalenyuk1111

Since they don’t let you know upfront, it is still not a good business practice from them.

How would I know that I need EU model if I am based in UK? Why would I choose wired thermostat if i wanted a wireless?

johnnyp78

Did you look at the tado shop? It explains which products have Opentherm https://uk.shop.tado.com/

It used to be the case that Tado didn’t explain which wireless receiver was which but now they do.

miyo

FYI, I specifically bought the EU model as I wanted OpenTherm support.