Nest E no longer firing combi boiler

[LizaB]

Hi there everyone 

I have a Vaillant ecoTEC plus 831 boiler connected to my Nest E that’s been working perfectly for a couple of years. It’s just stopped working/connecting to the thermostat. I’ve reset the heat link and thermostat, and reconnected them both. The thermostat dial thinks that it’s able to heat, there is a click on the heat link when I set it to heat, but the central heating doesn’t fire. Hot water is fine. Can anyone help?

Nest support are out of ideas…

[LizaB]

Correction - it’s been working fine for 3 years, and only just stopped 

[aperezdeleon]

Hello LizaB,

Thanks for reaching out to our community.

It can be confusing trying to figure out the reason your thermostat is not firing up your boiler. Let's figure it out together.

I would like to know if there’s any LED on the heat link and what’s the color of your Nest thermostat E display. Have you had any power cuts recently in your area or was there any recent maintenance done to your boiler?

You can figure out why your boiler isn’t firing up by activating manual mode on your heat link. You can do this by pressing the Heat Link’s button twice.

Does your boiler turn on after you activate manual mode? You can turn off manual mode by pressing your heat link’s button twice and then try to turn on the heating using the thermostat itself.

Please let me know what you find out and if there’s any error code on your thermostat after performing these tests.

Regards,
Angel.