Dual Zone confusion

H1ghland3r

Hi,

I've been happily using tado for many years but have moved to a new build house and have gotten lost trying to upgrade the installed system to tado.

I have a system boiler (with no apparent controller), a Mixergy HW tank and 2 wired thermostats controlling a dual zone system (Upstairs and down). Seemed simple enough but upon starting my install, the install guide tells me that my thermostats aren't actually thermostats they are programmers.!? (they are Myson Touch TS EU V2). I contacted tado and they tell me I need an extension kit for the boiler and potentially rewiring of the 2nd thermostats wiring to be compatible.

Does anyone have experience of what I need to do.? Failing that can anyone recommend a professional in the Edinburgh/S. Scotland area that understands tado because the half dozen or so heating engineers I have contacted so far refuse to touch it.!

johnnyp78

Assuming it’s a standard installation, you replace one programmer with a Tado wired thermostat and the other with a wireless receiver to control heating in the other zone and hot water. As Tado said, depending on how the heating and hot water is wired, you might need to rewire.

H1ghland3r

This is where I get lost. Neither of my current Myson units have any wiring for hot water. The Mixergy tank has independent control of water heating and manages its own schedule.

I have a picture of the wiring in the current thermostats if that helps.. there are a couple of other threads I found where people were replacing the same type of thermostat and they seem to only use 2 wired tado units, no extension kit.

johnnyp78

If there’s no hot water control wired in ignore Tado, you will be fine with two wired thermostats. If you get the Tado pro app or Google you can find links to installers manuals.

H1ghland3r

:D

That brings me right back to where I started on this journey as this was the setup I had assumed would be required.

So as a final confirmation then, the wiring would move the current NO and C wires to NO and COM on the tado units, the bridge wire is not needed and the neutral wire gets parked in P1/P2/P3.?

#EDIT : Obviously I meant the L wire goes to COM and the bridge wire is removed.

johnnyp78

If it’s a standard wiring job should be L on current thermostat to com on Tado and no to no. You should be able to park n. I would check your current thermostat manual though. Are both thermostats wired the same? There’s a generic Tado thermostat manual here https://cdn.brandfolder.io/607DGEMS/as/7k4rssnm8hbmr6mjf94qmck/104210-DIGITAL-ST01IB01-INSTALLER_MANUAL-TA-EN-00-V3.pdf

H1ghland3r

Ok, so I dug out the Myson thermostat manual and according to the wiring diagram in there, the NO is the switched live for the heating circuit and L is the permanent live as expected. Neutral looks to be wired to Neutral for Power input, pump and boiler. This all looks to be as expected.

So NO -> NO and L -> COM, park N

midland

Hi I'm in the same situation. Wondering if you went ahead as you described above and if it worked?

policywonk

@H1ghland3r .
You only took a shot of one of those stats. Would you add the photo of the other one?
Something is missing here.
When you have the time, please try to identify the electrical triggers route which force the boiler to power the hot water tank. Start by racing back the wires from its thermostat. There is probably another valve in the chain controlled by one of your Myson stats.

I don't believe it is a gravity system as it is in a new build. Having studied that model it also likely uses a pumped source of heat. So we need to find that before taking a final decision.

Do come back.