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H1 error. Can’t connect to heat link

Community Member

Hello everyone,

im having issue with connection between thermostat and heat link. It displays h1 error message.

Since last 2 years there was no issues. I’m trying to reset and paired again but no improvements.

I have been performing troubleshooting but no luck. Also I’ve been reading similar issues on this forum but nothing help. Is there any assistance in Ireland so I could call for technician? Or should I replace the unit?


Any advice?


Thank you




Community Specialist
Community Specialist

Hi VadiKus,


Thanks for reaching out. i'm sorry for the delay. An H1 message or code says 'Nest can’t connect to Heat Link and won’t be able to control your heating'. In addition, the Heat Link's status light will be yellow when it’s disconnected from your Nest Thermostat.


Follow the guides below:


Restart the Heat Link

  1. Hold down the Heat Link’s button until its light turns off. It should take about ten seconds.
  2. Release the button and wait for your Heat Link to restart.
  3. The status light will turn green if it re-connects to your thermostat. If the status light is yellow, continue to step 2.

Move your thermostat and test the connection


Your thermostat may be too far away from the Heat Link or there may be something interfering with the wireless Thread connection.


  1. If your thermostat is mounted on a stand (not the wall), try moving it a bit closer to where your Heat Link is installed.
  2. Check that there isn’t anything between your Heat Link and thermostat like a large mirror, or refrigerator. Large objects made of metal or other dense materials can block wireless signals.
  3. Check the wireless connection:
    • On your thermostat go to Settings > Equipment > Continue > Heat Link > Test.
  • If the test fails, move your thermostat again and re-test. Sometimes moving your thermostat a few centimetres can make a big difference.

Check your Heat Link installation


The wireless thermostat connection can be blocked if your Heat Link is installed too close to your boiler or hot water tank. Make sure that the Heat Link is installed at least 1 m (3.3 ft) away from your boiler or heating system. Reposition it if possible.


Caution: It’s important to protect you, your system and your thermostat. Turn off the power to your system at the fuse box before exposing or adjusting any wiring.

Reset the Heat Link to defaults


Try resetting the Heat Link and then reconnecting it to your thermostat. For complete instructions, please see How to restart the Heat Link or reset it to factory defaults.

In some cases, you may need to re-enter the Heat Link’s pairing code on your Nest Learning Thermostat. The code is a combination of six letters and numbers.


  • 3rd-gen Heat Links have the pairing code on the bottom
  • 2nd gen Heat Links have the pairing code underneath the cover, near the left screw hole.

Stop wireless interference from other electronics


  1. Other home products that use a 2.4 GHz wireless signal may cause interference. This includes cordless phones, baby monitors, microwave ovens and wireless security cameras. Try turning off these electronics one by one to see if your Google Nest Learning Thermostat and Heat Link are then able to establish a wireless connection.
  2. Once you have found out what’s causing the interference, try moving it further away from the Heat Link or Google Nest Learning Thermostat if possible and then recheck the Google Nest Learning Thermostat connection.