Tado Wired Thermostat replacing 3 wired Honeywell THR830T

Simon_P

Hi Folks, so I've just gotten my first set of Tado - the Wired Thermostat Starter Kit, I've downloaded the app and followed the setup instructions for self-installing the thermostat. But when I opened the Honeywell THR830T thermostat that I'm replacing, it would appear that the wiring there doesn't represent what the Tado guide suggests.

Attached are photos of the wiring diagram and the wired up original thermostat - simple question which wires (Currently marked 1, 2, 3 in the Honeywell thermostat) go where on the Tado thermostat? (i.e. NO / NC / COMM / P1 / P2 / P3 / A / - / + )

Many thanks

Simon

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luteijn

I /think/ you'd put '1' (live) on Tado's COMM, and '3' (switched on live going to heater) on the NO contact. You'd probably have to park '2' (neutral) on one of the P-spots, say P2. If you had a '4', it would go on NC (switched off live, e.g. to run a cooler).

Maybe it would be clearer if you double check where the other side of the wiring is connected, if visible.

luteijn

Still looks to me like the switch/relay should be between 1 (red) and 3 (yellow), and that 2 (blue) is neutral and is just there so a thermostat could be powered from the mains.
The tado uses batteries to be more universal, so it won't really be using that wire 2, so it can be parked on a 'P' contact.

https://www.explainthatstuff.com/thermostats.html seems to feature the thermostat you have. I'm not sure why it would really /need/ to be powered, but it probably has the 'small heater' (shown as the resistor/wavy line on the schematic) talked about here: https://flameport.com/electric/central_heating/room_thermostat.cs4

Simon_P

Here's the other side

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As for running a cooler - this is gas hot water radiator system, so nothing like a cooler...

...

Simon_P

Many thanks - that seems to work