Heat Link Not connecting to Thermostat - Error H71

[matthewanoop]

hallo,

I have Nest 3 rd generation Thermostat and Heat Link at home and since yesterday both are disconnected with error code H71. ( This happened after my gas engineer turned off the boiler, drained the heating pipes  replaced 2 radiators and recharged). I have 1 blue light turned on ( its binks occasionally)  on Heat Link and 2 green signs lighted up on Heat Link. I tried the 20 seconds trouble shooting as per YouTube videos and forums,  but no luck. 

Can anyone advice or guide me ? Is there a customer service  for NEST where I can speak to someone ? 

[Frustratedddd]

OK, try this. Make sure you only have the blue light and the 2 green ones are off.

Forget the 20 seconds that wrong, press and keep pressed the Heat Link button for 35 seconds or more. You will see the blue light blink as you are holding, but ignor everything until a good 35 - 40 seconds plus. Just keep pressed and you will see the blue light eventually pulse, then and only then release when you have a stable blue light pulsing . Do that twice to the Heat link.

Then at the display, look where it says ''Replace Heat Link''. Click that. Now you have to enter a 6 digit code found by the Heat Link cover fixing screw. Copy that down, and enter the code and follow the instructions.

Try that

By the way, if you had the H71 screen, chances are you had just a yellow light on the Heat Link. All you had to do was reset the display by pressing the display against the wall, until the house came back on!! that should have then worked.

[matthewanoop]

Thank you for the reply but this didn’t work. I have mentioned in my query as blue light Blinking, but actually my Heat Link pulsing through out. 
i tried 30-40 sec trick twice with Green signs turned off, but it’s still pulsing. 
when I keep pressed, it’s starts to blink fast for 10-15 seconds and then back to pulsing throgh out the 40 seconds. After I release my finger also the same. 
Any tips to fix this ?? 

 

[Frustratedddd]

OK, back to basics here....

The blue light will pulse even if reset on the first 20 seconds, that's not what we want here. The one you have now done is the one you need.

You need to check the following.

Make a note of the 6 digit code found on the Heat Link, by the left hand fixing screw under the cover. You will have to remove the Heat Link cover to see this. You will also see a 6 digit code on the lid by the cover screw. Do both numbers match to start of with?

Then on the display at the H71 screen you will see Tech at the bottom, open that and look for Heat Link, second down I think. Now open that and see what the 6 digit code is there.

Does all 3 numbers match, are they all the same?

[matthewanoop]

Hallo,

The number on Heat Link left to left screw and the one on bottom of the cover matches, but the 6 digit nummer on the Thermostat is different. I have attached a pic of it. 
blue light is still pulsing. 
Could please guide me further ?

 

 

[matthewanoop]

Hi,

I used the number on the Heatlink and it works now. Thank you so much for the Nest lessons. 🙂 I hope I did well as a trainee. 😄

[Frustratedddd]

That’s the reason your setup would not connect together.

Someone has changed either the display or the Heat Link, and you now do not have a matched pair. You will have to do that process every time you reset the system. A power cut like you had does not need that, you created an issue for yourself by resetting the Heat Link. All you had to do was restart the display. As I mentioned at the start. Remember that for future issues.

The resetting of the Heat Link at 40 seconds isn’t a trick, it sets the Heat Link back to factory, unlike the 20 second advice people give. 

Anyway you are back up and running.