Nest Thermostat 3rd generation no lights

[ClassicKiriyama]

Woke up this morning to an H71 error, not able to connect to Heat Link. No lights on the Heat Link.

Had a plumber out to check, confirms that the device is receiving power.

Device purchased 3 years and 1 month ago so out of warranty, but plumber suggested contacting Nest Support as a common issue, so here I am. Where do I go from here?

[AJAJ51]

Same thing happened to me this morning. I can't find a customer service number, but I did see instructions on charging it up. You remove it from the wall and replace the AAA batteries. In my case, it has to be charged with a USB. I'm charging it now. Let's see what happens. 

[TudorL]

Hi there and thanks for reaching our Community. I'm sorry to hear about your issues, but I'm here to help you out. Since it's the cold season and everybody wants to solve this ASAP, you can reach the live support line here: 

+44(0)-808-169-2307

Phone support hours:

• 8 AM to 7 PM GMT Monday to Friday
• 9 AM to 5 PM GMT Saturday to Sunday

If you're willing to continue the troubleshooting here, I'll need to document the issue a bit: 

What type of Nest thermostat do you have? 
When was it installed?
Are you seeing any wiring reports or errors on the thermostat and/or the app? 
Have you recently had service or maintenance on your electrical, plumbing, or heating system? 
Were there any power outages? 
Have you tried any troubleshooting steps before contacting us?

Additionally, please check the following: 

Step 1: Check if the Heat Link is powering on.
Step 2: Check the batteries in the Thermostat E Heat Link 
Step 3: Check if the issue is due to a power outage. 
Step 4: Check if the cause may be related to the initial installation. 
Step 5: Check if there has been any recent electrical or plumbing work carried out. 
Step 6: Check that the breaker switches are set to on. 
Step 7: Turn the fuse board switches (circuit breakers) off and on.
Step 8: Turn on Manual Mode to verify boiler activation.

[AlexD]

Hi, I wanted to check in. Did you see my colleague's message? Keep us posted.