Heat link defect

[Lutz]

Heat link defect sudden death. No lights, completely unresponsive. Thersmostat shows H72 fault. Ran all checks. Power supply still good and uninterrupted. Please support we are getting really cold

[george_t]

Hi @Lutz,

I'll do my best to get this sorted for you. Please answer the following questions:

1. What type of Nest thermostat do you have?
2. When was it installed?
3. Did the issue happen during installation or after installation? Was it installed by a Nest Pro or by a regular installer?
4. Are there any lights on the Heat Link? Does the boiler activate when calling for heat by pressing the Heat Link's button to activate Manual Mode?
5. Have you had any recent power cuts in your area? If yes, has the power been restored?
6. Have you recently had service or maintenance on your electrical, plumbing, or heating system?

[Lutz]

Thx!

1. Gen3

2. Febr. 2019

3. During normal operation. It worked well since installation and up to now. Installed by: self

4. All lights off. No response upon pushing the button Unless powered by external micro USB. (then manual mode possible).

5. No power cuts at all. The Netherlands, stable power grid.

6. No maintenance to heating system in last two years. The heating system does work in manual mode. It does provide hot water. It does supply power to heat link (verified) and both power cables and control cables are stable connected. Nothing changed since installation. 

[george_t]

Thanks for letting me know. Please check these troubleshooting steps and let me know the result:

1. Turn on Manual Mode on the Heat Link to verify boiler activation by pressing its button once. Does anything happen?
2. Check that the breaker switches are set to on or the fuse board hasn't tripped.
3. In some cases the boiler will have an additional isolation switch which can turn off the power to both the Heat Link and the boiler. Can you try switching that off/on again to see if anything changes? If you don't have an isolation switch for the boiler, turn the fuse board switches (circuit breakers) off and on.
4. Press and hold the Nest button in the middle of the Heat Link for at least 30 seconds. Are there any changes?

[Lutz]

1. Yes in manual mode (only if powered by external micro usb) it activates the boiler. 
2 all ok

3 no change after

4 no change after

[Lutz]

What’s next?

lutz

[AlexD]

Thanks for trying. In this case it would be best to get in touch with our colleagues over one of our support lines so they can make a case for you and help you get things back on track. You can use this link here.

No matter which line you choose you can also provide them a link to this thread here, they can see all we discussed and take it from there. 

[CristianC]

Hi there. Just checking in. How's it going with your Heat Link?

[CristianC]

It's been a while since this thread was last updated so I'll go ahead and lock this thread. If you're still experiencing problems, please feel free to start a new thread and we'll be happy to help.