Potterton Powermax HE and Google Nest

[Gosforth]

Hi I have taken the plunge and bought a Google Nest 3rd Gen that will control both the heating and hot water. There is also a Honeywell thermostat but we tend to use the programmer as the thermostat is in a stupid place in the hallway which is freezing cold next to the door next to the radiator which is isolated.

I was intending to use the Nest on a Stand. My question is the wiring as it seems slightly different to other posts I have seen. Is it simply a case of connecting new electrical wiring to the terminals ?

So Loop Tr to Tl

N2 and L2 to N & L on Nest link

HWr & HWl to 5&6 on Nest

CHr & CHl to 2&3 on Nest Link

Also flick the internal programming switch to off

Any help would be greatly appreciated.

 

[CBW]

Is that a Combi boiler? Seems to me that the 2 wires for the existing go to the Nest along with power.

 

[Rodders53]

That sounds right, looking at the manual for the boiler with HW store tank in a box Specifically p36.

https://www.freeboilermanuals.com/assets/pdf/potterton/Potterton-PowermaxHE.pdf

New wiring from boiler terminals (removing link wires existing) to the Nest unit wiring box (and disable the boiler internal timer-control via switch).

You'd remove the room stat wires from Tr and TL and use one of the link wires to give the Nest thermostat control. Or turn the existing room stat up to max.

Nest has the volt-free contacts Potterton ask for, so Nest switch closures should make boiler work.

You will need 6 core plus earth cable (or 2+E and 4+E) to effect the neatest install.

 

[ianmcd]

The nest will work of sorts with your setup, but if the core temp depletes then the heating wont come on untill the core temp is above the set temp, so if someone has a bath or a long shower and your radiators start cooling then heating again, then that is your unit just doing what it does