Installing Nest on a WB boiler

[GavBrum]

Hello Both and anyone else who might help with this.
I have a similar Worcester boiler and trying to install a nest, I followed the above and it makes sense generally but i have a few questions if you have time.
1. Why doesn't any of this look like the circuit diagrams in the Nest Manual?
2. The only earth connection i have on the nest system is next to the T1 and T2 connections. Looking at the nest manual it says that this is the earth if using T1 and T2. I don't want the external temperature sensor (as wasn't used by howto1 in this above) So I don't think I should connect it, why did you think that needs connecting Johnmdc? Was it just based on the page from the nest manual posted?
3. My boiler has lots of other connections like frost protection etc I guess Nest does this automatically with just the heating wires it has so that is why nothing gets connected on to this?

Thanks for any help.

 

[stem]

1. Why doesn't any of this look like the circuit diagrams in the Nest Manual?

All systems are different in terms of the components used so boiler manufacturers will either show their own products or one particular brand. It would be impossible to show every variant, however someone able to understand wiring and circuits (which you would need to do at this level of DIY) should be able to work out the functions quite easily and relate them to substitute products.

2. The only earth connection i have on the nest system is next to the T1 and T2 connections. Looking at the nest manual it says that this is the earth if using T1 and T2.

Heatlink terminals T1 and T2 are there to provide a 12v supply to the Nest thermostat if you would rather power it from the Heatlink than use a separate plug in power supply. They are nothing to do with the earth terminal. The remote nest Thermostat being 12v doesn't need an earth and so doesn't even have an earth terminal to connect it to.

3. My boiler has lots of other connections like frost protection etc I guess Nest does this automatically with just the heating wires it has so that is why nothing gets connected on to this?

A separate frost protection system located in an area prone to freezing with a remote frost thermostat is a separate identity and has nothing to do with the Nest, it should be wired in so that it overrides the Nest and turns the heating on even if the Nest is not calling for heat. Usually this is used when the boiler is in an outbuilding, or similar. Not all systems need this facility.

 

[DP]

I take it you do not have temperature control of water being heated in the cylinder.
Would appear there is a lack of use of proper heating controls or simply lack of these