How to bridge a Drayton Combi Stat to enable Tado Wireless receiver to work correctly
Hi.
Today I had the EU Wireless Receiver delivered to complete my system, however I believe I need to "bridge" the legacy wall mounted Drayton Combi Stat.
Does anyone know how to do this?
My system is as follows....
----------------
Vaillant ecoTEC plus 837 combi boiler.
No hot water tank.
Tado Basic rad thermostat and Wireless temperature sensor in each room.
----------------
Up until now, I have simply left the Drayton Combi Stat set to full and allowed the Tado devices to control each room, and so far it seems to have worked fine.
However I thought I'd complete the setup with a Wireless Receiver.
Followed all instructions, however even though the "heating" light comes on when the devices call for heat, it does not fire the boiler and currently seems to have no control over the boiler whilst the Drayton Combi Stat is still inline.
Therefore I believe that I need to "bridge" it in order to allow the Wireless Receiver to truly take control.
Drayton Combi Stat looks like this...
And the inside looks like this..
Many thanks,
Andy.
Answers
-
Can you take a photo of the wiring inside the boiler? In theory you could just park those wires but it may not be that simple.0
-
Hi @johnnyp78
Inside of boiler...
The Tado Wirelress Receiver is connected to the "Bus" terminals as per the instructions I followed.
Thanks.
0 -
I can’t see anything connected to the bus terminals (in orange) unless I’m missing something.0
-
Oh, that is the "before" picture...
Gimme 5 and i'll get the current pics...
0 -
Inside boiler:
Inside receiver:
------------------
Instructions...
0 -
I would just take the relay wires out. You could leave the l and n wires running to the wireless receiver in, though on some ebus connections you don’t even need them so could try removing them too.0
-
Could you please advise me which wires are the relay wires?
Is it the yellow wire on the right labelled RT?0 -
Yup, the yellow wire into RT and the l and n wires going to your old thermostat. Not sure where that yellow wire going to the ground terminal on the blue block is going - is there anything else connected to the boiler?0
-
The black cable highlighted in the pic below is the mains power supply and connects to the blue block..
I'll try disconnecting the yellow wire from RT and will let you know what happens shortly..
0 -
Ah I get you now, just the yellow wire from rt then. If you don’t disconnect the l and n wires going to the old thermostat make sure you park them at the thermostat end.0
-
OK, so I have disconnected the yellow wire from the RT terminal..
Powered everything back on, turned up the rads to call for heat and the heating light illuminates on the Tado wireless receiver, but the boiler does nothing.
I can also confirm that moving the dial on the legacy Drayton Combi Stat also now does nothing, so the yellow wire is definitely the correct wire.
I can also confirm that when I turn on a hot water tap, the boiler still fires for that and delivers hot water.
I'm guessing we're still missing something?
I'm also going to try contacting support to see if I can come at this from multiple angles.
Will keep you updated...
Thanks, Andy.
0 -
You’ve got a combi boiler so providing hot water is nothing to do with Tado. Have you downloaded the Tado pro app? If not I recommend doing that and making sure the wireless receiver is set up for a digital connection. I’d also have a look in your boiler manual and see if there needs to be a jumper put in (or removed) anywhere.0
-
There is only the yellow wire to the RT terminal and a L to the Live terminal, no N wire.
When you say "park them" what do you mean by that?
0 -
You’ve got three wires going to that old thermostat- l (red/brown), n (blue) and yellow (com). Park means take out of circuit and make sure they can’t touch each other or anything else as they’re still live.0
-
Yes, I tried the pro app yesterday, but didn't help.
Even if I was to find the boiler manual, I'm not sure I would know what to look for and so will wait for support to get back to me. Hopefully they can get things moving.
However many thanks for your replies Johnny. Much appreciated 👍
0 -
Oh I see... OK, will give that a shot and will let you know. Thanks...
0 -
That isn’t going to solve it though I don’t think. Like I said check on the tado pro app how the wireless receiver is set up. Check boiler manual to see if jumper required for digi connections. You can set correct config for vaillant ebus through your smart thermostat (I think d07 but not sure). https://cdn.brandfolder.io/607DGEMS/as/j4mjvsgpjtghjkm57fkx5q7h/104204-DIGITAL-WRB01IB01-INSTALLER_MANUAL-TA-EN-00-V3.pdf0
-
OK, so fully disconnected the Drayton Combi Stat, powered it all on and still in the same position.
Hot water still works but boiler doesn't fire for heating.
0 -
Did you follow the other steps?0
-
OK, so looking at the link to the manual you provided, I can see the following which was done during the initial installation...
Looking again at the Tado pro app, I found the following..
Does this mean I need to bridge this white terminal?
0 -
You’re looking at the wiring instructions. You need to follow the steps in step 6 of the wireless receiver manual to set up config correctly and use system check on the Tado pro app. Looks like you can also configure through the Tado pro app under configuration if you’d rather not do it through the smart thermostat.0
-
You also need to look at your boiler manual and make sure there are no jumpers needed if you use a bus connection.
I see you’ve said on the config that you have a timer installed on the boiler. That will need to be set to always on or removed.0 -
OK, went through the config process in the Tado pro app which appeared to complete successfully, however no change in boiler behavior.
Downloaded the manual for the boiler but couldn't find what I was looking for.
Can confirm that I have removed the time from the front of the boiler.
In the end, I decided to just go for it and bridged the RT24v terminal, rebooted the whole system and VOILA!
The boiler fires up and starts pushing heat to the rads !! 😲
0 -
This might sound like a stupid question but does the boiler turn off when you click ‘turn off all rooms’? If not then it might just be shorted to permanently on.0
-
Yes, this was one of the 1st tests I tried to make sure it genuinely turns off the boiler.
After around a minute, the heating light on the receiver goes out and the boiler shuts down.
Run a hot tap, and the boiler fires up to provide hot water, turn off the tap and the boiler shuts down.
Obviously I'll be keeping a close eye on it to make sure it is behaving as expected over the next few days or so.
However just wanted to again say thanks @johnnyp78 for all of your help 😀
2 -
No worries, you seemed like you were on the right track with it anyway!1
