wiring wired tado

bazantus

hi, the 'customised' instructions were as clear as mud so here I am.
an old setup so a bit more quirky:

• an old Danfoss timer + thermostat that is connected to the timer
• potterton promax he plus boiler

the timer identifies ON, COM, L and N - but there is a bit of a maze of cables. can anyne suggest what the correct way to get it replaced be:

• should I remove the thermostat and the cables going to the timer
• then connect Tado to the remaining cables connecting to the timer? there are 2 cables coming from the boiler (one going to N and L)

any help much appreciated

Emcee

Hello @bazantus,

With these types wiring / cable questions, it really is best to contact tado° support. Many of our community members are very well informed and could potentially help you, but the safest bet is to talk to the professionals in this instance. You can begin your conversation with support by clicking the chatbot icon at the bottom right of your screen.

bazantus

Tried. Tado support is saying they only provide support for single device and will not advise on how to replace both the timer and thermostat (no idea why but hey…). So I hope some well informed member can help here.

I mapped out the wire connections to and between the timer and thermostat. The timer is the main hub and the simple thermostat connects to it with additional wiring (i.e., no direct cables between the boiler and the thermostat).

TIMER TERMINAL → Boiler Connections	TIMER TERMINAL → Thermostat Connections	THERMOSTAT TERMINAL
CABLE 1 (connects to the boiler):  Brown --> terminal 1 (ON) Blue --> terminal 2  no earth.	CABLE 3 (connects to the Danfoss thermostat) Blue --> 2 Brown --> 3 (COM) Earth --> 4	CABLE 3 (Danfoss thermostat) Blue & Brown are both going into ON
CABLE 2 (connects to the boiler): Blue --> terminal 5 (N) Brown --> terminal 6 (L) Earth --> terminal 4	CABLE 4 (connects to the Danfoss thermostat) Earth --> 4 Blue --> 5 (N) Blue --> 6 (L)	CABLE 4 (Danfoss thermostat) Blue —> N Brown —> L

Note that CABLE 3 is basically one wire as it goes into one single terminal. Ideally I want to remove the thermostat AND the timer and place TADO where the timer sits: there would only be CABLE 1 (ON & unsure) and CABLE 2 (which seems to be destined for L and N).

thanks in advance,

bazantus

Unfortunately, Tado's engineers have tied hands as this requires bridging (probably H&S kicking in so they cannot provide instructions).
I worked out the the set up - including bridge - but wanted to run it by more knowledgable folks here to make sure I did not miss some detail.

Here is the whole current wiring. If anyone can comment on how to completely bypass the timer and thermostat (both making a lot of noise due to their age) that would be great.

bazantus

ps. I am aware that the current wiring makes no sense and the thermostat will do absolutely nothing (probably the same person who did some 'upgrades' to the plumbing!). and so need to replace both.

hugbilly

I would suggest the most straightforward way of approaching this would be to replace the time clock with a wireless receiver and then use a wireless temperature sensor + TRVs as required but you don’t state whether the boiler is a combi and what the hot water arrangement is.

bazantus

yes, combi (Potterton promax he plus) but no need for HW control: just needs heating control