Google nest thermostat only working in manual mode

[Sallyobie]

Hi,

We recently installed a google nest thermostat into our new heating system. Unfortunately, the heating will not turn on using the app or via controls on the thermostat.

I have reset all settings and there is a connection to heat link.

When in manual mode, I can turn the heating off using the app. I can hear the click in the heating link when turning the heating off using the app but there is no click sound when I try to turn on the heating.

[Frustratedddd]

The first thing you need to do is check the relays are switching in the Heat Link. Test terminals 1-2-3 for the heating.

Which terminals are connected at the Heat Link?, upload a picture of the terminations to make life easy.