Sundial RF2 to Smart Thermostat

[SixSevenEight]

Hi,

I’m looking to fit my Tado system to my new house, I had it in my old house and it was a simple swap there...

However new house has a Honeywell Sundial RF2 Pack 3 (wireless HW and CH stats), and Tado requires a wired HW stat.

System is a Grant Oil Boiler, S Plan configuration.

I’ve run the wiring already for the HW stat (high temp 4 core), and bought a new Honeywell wired stat.

I just need to work out how to wire it into the existing Honeywell wiring centre - as it looks slightly different to what I expected.

There are terminal blocks linking the controller HW/CH on wires direct to the 2 port valves brown wires.

Also the links that have been cut didn’t seem to correspond exactly with what I’d read online should have been cut.

I have a spare Wiring Centre if it does need to be redone.

Any help appreciated!

 

[SixSevenEight]

Looking into this more, the terminal block linking Controller HW On and the HW Valve’s Brown is presumably just a short of the “Cyl Stat” within the Centre.

So if I disconnect the terminal block, plug those two wires back where they are supposed to go - and then hook up the HW thermostat wires into the right place it should work right??

 

[mrStat]

Sorry, roll back a bit, I am guessing you are fitting the extension kit and as that junction box is not wired up as it was originally intended, you should be able to go to HW on and then wire the cylinder stat C,1&2. This would make it easier to diagnose in the future, however I cannot remember what all the links do and some of the links interrupt signals, so I’d personally opt for a simpler approach....

Effectively:
- At clock
Replace the clock with the extension kit backplate, like4like. No changes needed.

- At junction box
The grey wire with brown sleeve, connected into the connector block with the brown wire. This grey wire needs to go to your new wire and connected to cylinder stat COM and then the cylinder stat CALL needs to go to the brown wire that was connected to the grey.

 

[SixSevenEight]

Thanks - that did the job, further investigation with a multimeter showed which terminals were joined up so I managed to neaten up the wiring at the same time (less terminal blocks)