Nest Thermostat and heatlink wifi connection

[stevennicholson]

The heatlink  (3/4 years old) is  intermittently failing to respond to the thermostat. This has happened a couple of times through the last couple of years and I go through the tiresome issue of factory reset of both heatlink and thermostat and generally comes back on.

This time the heatlink has failed to respond wirelessly again after only 48 hours from a full reset. I saw some feedback in a forum that there is a Known weak wifi component that fails in the heatlink but google are not being clear about it. Not sure what to do know. I also heard that google were replacing this equipment last year for this issue but don't know if this  is still the case. Help!!!!!

[Vladut]

Hi there, thank you so much for reaching out. I'm very sorry about this situation. Can you tell me if you notice any message or code about this?

[stevennicholson]

Thanks for your reply.

No, there is no failure code.

The failure mode is that the heatlink is on green as it should be and the thermostat is orange showing the demand temperature. There is no change in wifi network which is stable and has been for 2 years without interuption. Yet the Worcester Bosch combi boiler dos not show the usual green demand light on the boiler instruments. It seems the heatlink is stuck and hangs without correction. 

I had to reset to factory settings heatsink and thermostat and start again as a new nest thermostat with re doing connection to wifi and pairing etc etc. This time it failed again straight after setting and I got it to communicate again by going to manual  on heatlink for a few minutes and then started responding again when going back to auto.

The heatlink and thermostat work well usually so this is an intermittent issue. I have however noticed that this happens particularly as we move from summer to autumn/winter as the heating gets turned on. The thermostat and heatlink almost forgot how to communicate during the summer layoff.

The heatlink and thermostat are only a couple of years old so not obsolescent kit. 

[Vladut]

Is the thermostat on the wall or on a stand?

[stevennicholson]

Just on the stand, Just wifi no wiring. when the problem emerges I moved the thermostat to within 2 meters and it didn't make any difference.

[Vladut]

Next time when it happens, can you please follow these steps: 
Turn off the WiFi router.

1. Reset the Heat Link by keeping the button on it pressed for 30 seconds until the LED goes slowly pulsing blue.
2. Take the thermostat off the base and give it a restart, off the base by holding the display and the back of the thermostat pressed for 10-12 seconds. (Hamburger reset) 
3. While the thermostat is restarting, do not put it back on the base yet, but instead, reset the Heat Link again just like before.
4. After the Heat Link is reset, put the thermostat back on the base when it asks you to do so on the screen. 
5. Go to: Replace Heat Link (underneath the H71 error code) and enter the 6 character entry key from the Heat Link, but do not connect just yet.
6. Restart the Heat Link twice (1 restart is a 10 seconds press, until the LED goes off once). 
7. Press connect on the display.

[stevennicholson]

Wow, that's complex, but thanks for your support.

in point 5 is the heatlink code you mention assigned or do I need to find it on the heatlink somewhere?

[Vladut]

You'll find it on the Heat Link on the bottom right near the screw. So sorry if it appears complex but I can assure these are the most stable steps you can do.

[stevennicholson]

Thanks again, so what is the issue then?  How would you scribe this weakness?

A glitch? a software synchronisation issue? a coding discrepancy?

[Vladut]

Based on what you mentioned so far, it seems more likely an interference issue. Either physical or radio interference. Do you have the means to bring it closer to the Heat Link with a power supply?

[stevennicholson]

One factor that for me rules out interference is that this only happened as we switched from  summer season and start to use the thermostat/heatlink for Central heating. The first time we put a demand on the thermostat after a long period of inactivity , it will not communicate with the heatlink. I think this is a clearer description of the failure mode. Apologies I didn't make this so clear until now. However this time we had a repeat of not communication after a reset , which never happened before. Nothing else has changed in the set up or regarding any equipment surrounding the systems so no new RF type interference.

[AlexD]

Thank you for all the information provided. Just to make sure I got things right. You set it to heat, for example, the display on the thermostat goes orange, so the heating would be on, but the boiler has no reaction to that, correct? It does not fire up. 

Do you have only heating or do you have heating and hot water control on the thermostat? 

[stevennicholson]

Yes your scenario description is correct. 

and following that I can get the heatlink and thermostat to communicate by temoprarily triggering the heatlink manually for a few seconds then switching back to auto/wifi. This worked at the time of having the problem and the problem has not yet returned. Its been 4 days now but I am not confident the root problem is resolved.

I only have central heating on the nest thermostat. Domestic hot water demand is triggered  by pressure drop directly with combi boiler.

[AlexD]

Thanks for the information. For now keep an eye on it. 

If you notice this occurring again make sure to take note of the colour of the display, the set temperature and ambient temperature at that moment. Also check on the Heat Link and note the colour of the LED on it at that moment. 

If it's a Combi boiler then yes, hot water will be on demand. 

Do you happen to have any separate programmers or valves at the location, like in a zoned system with multiple thermostats? 

[stevennicholson]

thanks for your help so far.

No there is no separate programmes or zoning, it's a very simple set up. As I mentioned previously there is no new/changed equipment in the building that I am aware of that would cause RF or other interference .

[AlexD]

Ok in that case for now wait and see if the behaviour occurs again and note the status of the ambient temperature and set temperature as well as the LED on the Heat link. 

Also perform this test if it does occur again. Go next to the Heat Link and open the Nest app on a mobile device:

1. Select your thermostat to access the heating controls and make sure the screen is black, heating is off.
2. Turn up the temperature until the display goes orange, heating on, and listen for a clicking noise.
3. Turn the temperature back down until the display is black again, heating off, and listen for a clicking noise again.

[stevennicholson]

ok will do, thanks again.

[AlexD]

No worries. Keep us posted here on how things go. 

[Vladut]

Hi there, just checking in with you. Did you manage to check the above steps?

[stevennicholson]

Not yet, I didn't want to disturb it whilst it is working ok. If it drops out again I will use your instruction to reboot it.

[LarisaL]

Hi there! Understood. Keep us posted. 

[Vladut]

Hi there, just checking in with you. Do you still need help?

[stevennicholson]

Don’t know until it happens again. ?

[stevennicholson]

Don’t know until it happens again

[LarisaL]

Understood. In this case, please let us know if the issue persists or if you have any new issues, updates or just a discussion topic, feel free to start a new thread in the community. Thanks, Larisa.