Nest 3rd Gen Learning Thermostat

[ConnorMcG]

Hi I've bought a new Nest 3rd gen Learning, I've connected it up and got power to the heat link and wordlessly connected to the thermostat but the thermostat was running on its battery and there's no voltage coming of the t1 and t2 terminals, I have a 2 dual zone heating system with a thermostat in the living room just controlling that 1 radiator and a second thermostat in the hallway controlling the rest of the house (does not controll the living room) I can't find the motorised valve or gravity valve yet, to wire it in place of the current thermostat, I would have to find these connections and make them permanently live to get the heating to work if I am correct? as thats the reason it wouldnt work wirelessly? does this mean I need to replace the heat link as no voltage coming out of the t1 and t2 terminals? 

I have a logic combi boiler espi 35 

[Frustratedddd]

You are saying new, is this new boxed and sealed from a shop?

Have you checked the voltage out of the Heat Link terminals, at the Heat link not the display base ring?

Easy way to get the display connected to the Heat Link as a temp job, is connect a micro usb to the base plate, then put the display on the base plate. That will prove the display and display base ring are OK.

Before you go any further, check that first

[ConnorMcG · Accepted solution]

Hi, yes I ordered it from eBay, came sealed in the box but never received a USB with it, I can plug USB into the thermostat and in the power settings it will say its powered from USB but then when I wire into the heat link the power is just from the battery, but yes I've tested both terminals at the heat link and at the thermostat base whilst connected and no voltage there, the heat link light is on and I can connect wirelessly to the thermostat but does not control the heating, dont know if that's due to not enough voltage from the 5v USB or the 3v from the thermostat battery or because of the original wiring as that activates the heat flow to the radiators which I've been unable to find the motorised/gravity valve, but there should be dc voltage coming from the heat links T1 and T2 terminals right?

[Frustratedddd]

OK, You will not get a usb cable with a new 3rd generation thermostat these days, that stopped years ago.  You say no voltage out of terminals T1 or T2, if you have power to the Heat Link as you say you do, then the Heat Link is faulty. Assuming you have tested direct on the terminations at the Heat Link, not the cable coming out.  Very unusual a new sealed Heat Link faulty, but who knows.

Upload a picture of the Heat Link connections, and that might help us.

[SofieQ]

I can’t seem to find the heating n cooling control on my panel. Used to be there but it’s not there anymore