Nest 3rd gen thermostat stuck in h71 screen

[Mostyngoodwin]

Hello. Our wireless thermostat has started dropping connectivity to the heatlink multiple times a day. We swapped to a 2.4 ghz wifi signal to try to help. I removed the existing WiFi network but the thermostat started searching for the heatlink on the h71 error screen. Given it is not on the network it cannot find the heatlink, and I cannot find a way out of the h71 screen. 

If I manage to somehow get out the h71 cul-de-sac, and reenter the network, any ideas not dropping the signal. It is mains powered but battery only showing 3.6. Ibis next to a large wifi booster. Thanks

[Frustratedddd · Accepted solution]

You say you enter the 6 digit code from the Heat link, I assume you mean the one found on the Heat Link cover?

Just to check a couple of things first... when at the H71 screen go to ''Tech Info'' - ''Heat link'' and check the 6 digit entry key number is the same as on the Heat Link. Check the 6 digit code is the same on both the cover of the Heat link left hand fixing screw. Should all these numbers be the same, that is good.

Now, assuming all the number smatch, the only way you will get this to work is with a hard wired cable as I first mentioned. You only need a temp connection, and this is really easy to do, even if you connect from the Heat Link to The Base Ring while held in your hand. You just need to get the thermostat back up and running first.

Once paired you can the hopefully try the wirless connection, then when all working, do a full factory reset.

I come across this a lot, and sadly this is the easy and best way to prove. I think the set is confused, and needs resetting.

Hope that makes sense.

[Mostyngoodwin]

Replying to this thread. I managed to factory reset and when restarting got to enter the network details. So the thermostat is now on the network but I cannot find the heatlink. I tried holding the button  on the heatlink until it flashed blue after 45 seconds twice but still cannot connect

Power only 3.7w but connected to mains so not sure what I can do to increase power

[Frustratedddd]

You say the wifi is now 2.4, are you connected direct to the router and NOT via the booster? Boosters do give connection problems, and always best to connect direct.

Battery power works at 3.7v, regardless of the people saying it has to be 3.9v, yes higher the better of course.

You say you are mains connected? Do you mean connected via the Heat Link or plugged into a mains USB adapter? Should the answer be to a USB adapter, then the best method is wired direct to the Heat Link. For a test to make sure the thermostat is talking to the Heat Link even a temp connection would do. For example run a cable from the heat link to the base ring anyway you can, an old bit of flex will do just connected from one to another. Doesn't matter what it looks like to get a connection, the you should be able to get past the H71 screen.

You also mention a large wifi booster, has the problem started since you installed that? That could be an issue for interference, blocking the signal! Nest do not like metal objects and signals etc.

One other thing, have you ever changed one of the parts, ie Display or Heat Link from the original set?

[Mostyngoodwin]

Thankyou so much for the reply. Yes 2.4ghz and direct. Thanks re 2.7w ref the battery. The thermostat is USB connected to mains plus and WiFi connected in theory to heatlink. Post the factory reset I manged to skip the h71 screen and now have the thermostat on WiFi but it is refusing to pair with the heatlink even though 1m apart. I have tried the 45 second heatlink reset twice in succession to get the flashing blue light but refuses to pair with the heatlink

[Frustratedddd]

The wifi and the Heat link/Display connection are nothing to do with each other, they are seperate connections, Just for your info.

I asked if you had replaced any part of the setup, have you? ie, new display or heat link?

[Mostyngoodwin]

Thanks. Nothing new but I factory reset the thermostat as it was stuck in an h71 menu. Post entering  location, network etc it looks for the heatlink but can't find it despite entering the 6 digit code and having the blue  light on the heatlink flashing. I  wonder whether reseting the thermostat means that the heatlink will not accept the pairing?

[Frustratedddd · Accepted solution]

You say you enter the 6 digit code from the Heat link, I assume you mean the one found on the Heat Link cover?

Just to check a couple of things first... when at the H71 screen go to ''Tech Info'' - ''Heat link'' and check the 6 digit entry key number is the same as on the Heat Link. Check the 6 digit code is the same on both the cover of the Heat link left hand fixing screw. Should all these numbers be the same, that is good.

Now, assuming all the number smatch, the only way you will get this to work is with a hard wired cable as I first mentioned. You only need a temp connection, and this is really easy to do, even if you connect from the Heat Link to The Base Ring while held in your hand. You just need to get the thermostat back up and running first.

Once paired you can the hopefully try the wirless connection, then when all working, do a full factory reset.

I come across this a lot, and sadly this is the easy and best way to prove. I think the set is confused, and needs resetting.

Hope that makes sense.

[Mostyngoodwin]

thankyou hugely. yes the 6 digit numbers match so will need to try the hardwiring option. from other threads it looks like either of the t1 or t2 ports on the heatlink ? where do i wire into on the nest thermostat base ring? sorry for stupid questions - i cannot see simple fix online. thanks again 

[Mostyngoodwin]

presume to the same t1 or t2 ports behind the screws on the plate i just found?! i will give that a go

[Frustratedddd · Accepted solution]

Ah, now there's a question!!!!

Yes correct.

T1 & T2 on the far right hand side of the Heat Link are the 12v power out.

The base ring is tricky, as it only has 2 terminals! Sorry, just could not resist that!

Just connect 2 wires from the T1 & T2 on the Heat Link direct to  the terminals on the base ring. Does not matter which cable goes in which hole they are not polarity important, just connect them, see quick image I have added. This is really simple believe me, this will take all of 5/10 mins to do.

[Mostyngoodwin]

Connected the thermostat to the base ring with wires. Connection fine thanks!. But still refuses to connect wirelessly despite being 1 yard apart, correct 6 digit code and value flashing light on the heatlink

[Mostyngoodwin]

Did a factory reset as suggested and now it picked up the heatlink. Thanks hugely

[Frustratedddd]

There you go, well done.

A common problem, but people just are not aware how to get round this issue sometimes.

You now know the trick!!

[AlexD]

Thanks for reaching out to us here @Mostyngoodwin . I see things are already back on track. Thank you for all the assistance provided @Frustratedddd, amazing job. 

Once the wired connection is established you can reset it, establish the wired connection and then disconnect it. This should only leave only the wireless connection. This would generally be the last thing we would try, once we go through all the other steps and only if possible of course, as not everyone is comfortable wiring the display to the Heat Link. I am happy to hear that it worked and you got it connected. 

Do keep an eye on the connection though and let me know if you notice drops again and we can have a look at it if needed.

[Vladut]

Hi there, just checking in with you. Did you manage to check the previous message?

[Paul_R]

Hello there! Since we haven't heard from you in a while, I'll close this thread for now. If anything comes up, feel free to reach out again.