Heatlink died UK - replaced but now thermostat temperature reading too high

[mainoooo]

Hi All,

Had a heatlink die overnight, engineer has been and replaced with a new unit. Now I have a new issue never experienced before. The thermostat is now showing the temperature way higher than it actually is. For instance the temp is showing as 20 degrees C but a thermometer is showing the house is actually 16 degrees C as not had any heating since the heatlink died.

Anyone else experienced this issue after they've had a new heatlink installed?

[Frustratedddd]

Are you saying the heat is still not calling when set at 20 on the display?

Did you have a Heat link or a complete new set?

The reason a higher reading at present could be to the learning feature settling in.

[mainoooo]

Hi - it's showing the ambient temperature of the hallway as 20 degrees but it's actually around 16 degrees. I can get the heat to come on by turning it 21 but my issue is the thermostat is now around 4 degrees out since having a new heatlink installed.

The installer only installed a new heatlink module then paired it to my existing gen 3 Nest.

I don't have the learning feature enabled, I've never had it enabled since installation in 2019.

Just can't understand why yesterday the temperature was reflecting accurately and today after new heatlink its 4 degrees out.

[Mikepatrij]

Check the voltage on your display is above 3.9v, I’ve just fitted a new display and it’s reading high temps, Google told me to check the voltage as this can cause it

on display go to Settings > technical info > power, it’s shows the unit voltage 

[mainoooo]

Hi @Mikepatrij  - Votlage is showing 3.922V

[Mikepatrij]

That’s a pity, just refitted mine and it’s adjusted to correct readings

Might be worth doing a full factory re-set on the display 

The engineer should have done a reset on the heat link and display 

Otherwise contact Google via chat or call them, they are very good

[Frustratedddd]

The voltage will do very little, and as long it's above 3.7v should be fine, 3.9v even better.

Does the display feel warm to touch by any chance, or normal?

The thermometer you mention, is that in the same place before you had the heat Link fitted? The only reason I ask, people get paranoid about the display setting and a thermometer reading.

Have you tried a restart, not full factory reset?

[mainoooo]

Display feels normal to touch like always. Thermometer is in same hallway location it's been in for 10+ years. Nest Thermostat installed 2019 and no issues up until today. Only thing that has changed today vs yesterday is having a new heatlink unit installed due to existing one failing overnight. I've done a full factory reset and that's not improved things sadly. 

When i remove the thermostat from the wall base plate and then put it back on the temp displays correctly (16 degrees C) then quickly rises to (20 degrees C)!

The thermostat did lose all battery power overnight as from my understanding the heatlink charges it (mine is connected via wire). Some suggestions on the internet point to battery being recharged might have warmed up the unit thus raising the temp of the sensor. Thoughts on this theory?

[Mikepatrij]

I charged the display using a usb connection, it’s takes approx 30 mins, I don’t think it will affect its temp reading, your voltage is correct

I would contact google support

[mainoooo]

The thermostat is now hot to touch so maybe it does have a fault - just struggling to understand how this coincided with the heatlink failure.

[Frustratedddd]

Having a new Heat link should not make any difference, but that does not mean the old Heat Link may have created an issue with your display.

Charging will cause heat from the battery, and that's why I asked if the display feels warm!

I would restart the display twice on the wired base you have installed, NOT reset.

I would then leave all alone for 24hrs or more, do not touch the settings or charge via the USB or anything, just see if the display settles. I would set the display for the required heating you need, and leave it alone. should that be higher than you normally have it, so be it.

After the 24hrs+, check to see if the display has settled back to what you think is normal, and also touch the display to see if warm. All good, then leave well alone.

Should the display still feel warm, and the temp setting is way out, then I think you will find the chip is faulty. I have come across this many times, and if taken apart you would see the chip discoloured. lets hope it's just a settling in issue.

See how you go.

Oh, and is the WIFI connection all working correctly?

[mainoooo]

Thanks @Frustratedddd - Last night restarted twice and have since left alone. Wi-Fi connection is working ok.

This morning the metal dial is cool to touch (it was warm last night) but the temp reading is still to high. Screen feels slightly cooler today. Will leave for another day or so.

If unit is faulty then i'm out of warranty but i might argue it's linked to the heatlink which they replaced out of warranty due to known issue.

[Frustratedddd]

That's good the heat is dropping, and I think or hope that could have been the battery charging. Should the display be still warm tonight say 6pm, then look at the voltage in the settings to see if you have reached 3.9v ish. Check also if the display reading has become more realistic. One other thing, are you both wired and wireless? Connect also to wireless if you are not, before you do any resetting.

Should all be exactly the same, and no improvement, then I would do one final FULL factory reset. Remember, now you have a non matched pair, you will have to click ''Replace Heat Link'' when it gets to that part and use the code on the new Heat Link, as the display will not find the Heat Link otherwise.

The reason I asked about the wifi, is the wifi chip when on it's way out gets hot, and that creates heat to the display. Google will never admit this as they want a fault code number, but again a common problem.

Yes you could always go back to Google and try for a replacement under those terms, but a faulty Heat Link probably would not cause your problem. I assume you had a replacement as the old one died?

Interesting you say you are out of warranty! Assuming you are in the UK, then consumer law would have covered you, even after 3 years, in fact up to about 5 years! I expect you didn't know that?

[Paul_R]

Hello @mainoooo ! I'm sorry to hear that you're experiencing this situation, but I'm here to help! I saw above, that you said the thermostat receives power from the Heat Link, and since the installation of the new Heat Link the display gets hot and shows a higher temperature than the real one. If the thermostat heats up, it's expected to show a higher temperature than the one in the room, so we should focus on the other aspect. Since the issue only appeared after the install of the new Heat Link, I assume there might be related to the wiring of the replacement. Could you please take the cover of the Heat Link off, and send a picture of the wiring? If there's anything wrong there, I'll be able to identify it. 

[mainoooo]

Hi @Paul_R  - great idea - how do I take the cover off?

[Paul_R]

There should be a small screw under the Heat Link. Unscrew it, and then it will come right off.

[mainoooo]

@Paul_R  - here’s a picture. 
https://postimg.cc/8snKSkXp

https://postimg.cc/DWyphWhz

[OannaCG]

Thanks for letting me know! I've sent you an email, please follow the instructions from it with the requested details and let me know once you've done it and will continue from there. 

[mainoooo]

@OannaCG  - form filled in.  

[OannaCG]

Thanks for letting me know! Just to make sure: the device is not next to a heating source or under direct sunlight , right? 

[mainoooo]

No the device is in the hallway where it has been since 2019. 
Issue only started after new heatlink installed under ‘Google’ warranty last week. It was absolutely fine up until that point. 

[OannaCG]

And is the thermostat warming up now like it did before or is it just that the ambient temperature is too high on the display? 

[mainoooo]

The thermostat will fire up and provide heat but it’s displaying an ambient temperature approx 3 degrees higher than it was before. Metal dial is warm to touch and screen is also warm to touch.  

[OannaCG]

Thanks for confirming! I escalated the case to the department in charge and as soon as I get any updates, I'll get back to you.

[AlexD]

I see our colleagues reached out to you over email to continue handling the situation. I will go ahead and close this thread, please stay in touch with our colleagues over email. If anything else comes up, feel free to open up a new thread.