Nest v3 installation.

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Hi,

I spent a few hours fitting this yesterday to a holiday home I own. Yplan boiler, hot water tank, thermostat in hall, timer in kitchen.
Once fitted, the wife was yacking at me to leave for the journey home, so I didn't get time to fully test it.

However, I did get time to fire up the boiler from the heating command and hot water command on the new Nest 'stat screen, albeit just for a few minutes. Also got testing the new 'stat was responding to my Iphone inputs. Didn't seem to be anything untoward and all seemed ok.


Later after I got home, I was playing around with the app, but I couldn't see any way to control the hot water remotely. On checking, there should be a water button showing on my Nest app on the phone, alongside the heating button. I can only see the heating button.

Would anyone have any idea why the app is not showing a control for the water?
I am going back up to the house tomorrow night to recheck the wiring. There may be a wiring issue on the HW side from the junction box to the Heatlink. I do recall though, that I fired up the boiler manually from the hot water function manually on the nest screen in the hall so Im a bit baffled.

Another thing that is really confusing me as I done a bit of research online tonight. I googled YPlan wiring diagrams and studied 3 or 4 of them from different sites. They were all the same as you would expect.
On all the wiring diagrams I viewed online, the Grey wire from the Y valve is connected to the Cylinder thermostat 2 connection, and the orange wire from the Y valve is connected to the Cylinder thermostat 1 connection.

On page 25 of the nest installation guide, its the opposite!
It shows the Grey wire from the Y valve is connected to the Cylinder thermostat 1 connection, and the orange wire from the Y valve is connected to the Cylinder thermostat 2 connection!!

See below photos as an example.

Which is correct? I would have presumed if the manual was wrong it would have been highlighted here, but by the same token, all the online wiring diagrams conflict with the Nest instructions re these terminals.
Its important because it asks for the grey wire from the Plan valve to be connected to terminal 4 on the heatsink. But Im unsure whether that Grey wire should also be connected to terminal 1 or 2 on the Cylinder thermostat.
I can't check my own system until tomorrow night, but thought I would ask re these two issues for your thoughts and opinions in the meantime.

Many thanks
 

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I can't comment on the operating software I'm afraid, but regarding the wiring, the grey wire is 'live' when hot water is not required. This 'live' comes from the cylinder thermostat when the cylinder is hot / up to the set temperature (ie hot water not required) and also from the programmer when the Hot Water is switched off (ie hot water not required)

This is how it is shown in both of the diagrams that you have posted. The diagrams show cylinder thermostats that are different models, so the terminal numbers do not correspond. You will have to check the connections for yours, to see which terminal does what. You can't rely on the terminal numbers unfortunately.

The orange wire is the switched live to the boiler. It switches the boiler 'on' when the central heating is required, but it is not used by the hot water, which uses the 'call' signal from the cylinder thermostat to fire the boiler.
 

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