Some Google Nest Thermostat users getting E102 & N72 errors with greyed out Rh wire

The Google Nest Thermostat is one of the best smart thermostats available on the market. Easy to install and use, it can be controlled via Wi-Fi and has built-in energy-saving features that can come in handy when you are not around.

One one of the best things about the Nest Thermostat is that users can easily control it using Google Assistant or using the Google Home app. Moreover, it can also detect issues with one’s HVAC systems.

Google-Nest-Thermostat

However, people who own the latest version of the Nest Thermostat have reported a bunch of issues with the devices, such as the recently reported bug where the hot water option was not working.

As it turns out, new bugs and glitches are still popping up. Nest Thermostat owners now say that they are getting Error N72 with a message that reads “Power wire Rh detected. No connection to equipment.”

User reports indicate that the issue persists on both existing and newly installed Thermostats, indicating that the hardware is not at fault as one would expect. Some say that they are getting the E102 error as well in addition to N72.

Google-Nest-Thermostat-Error-N72-E102
Source

I have the same exact problem happening right now. Installed Nest Learning on 1 April. Ran heat through May, then AC and Heat into June until we went to straight AC for summer. Multizone heating system (forced hot water) with two Nest E’s on other zones. Testing heating system from Nest Learning on 6 Oct. Taco box just kept clicking. You will see other posts about this across the web. Call heating company for PM b/c I assumed the problem was with boiler. First thing tech said when he arrived was “you have a Nest thermostat, correct?”. He performed the same troubleshoot you did (W to Rh wire – triggered heat).
(Source)

I have the same exact error and problem, same exact wiring setup as the original person who posted with the separate heat and cooling systems. The thermostat has been working well for the past 2 years. Within the past day, my Nest 3rd Gen started reporting E102 and N72 errors. I had the heating repair company here and he confirmed that the boiler, heating system and control are working by jumping the Rh and W1 wires. He proved that the issue is the Nest thermostat.
(Source)

This is really concerning since many rely on Thermostats to regulate their home temperature. A nonfunctional Thermostat is a nightmare for many, especially during winters.

With reports flooding in the last two weeks, it looks a botched-up software update has messed things up for Nest Thermostat users. Moreover, with Google yet to say anything on the matter, we wonder when Nest Thermostat Error N72 and E 102 will be fixed.

Nonetheless, we’ll keep an active track of the developments on this one and update the story, as and when required.

Note: We have more such stories in our dedicated Gaming Section so be sure to follow them as well.

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Anurag Chawake

My fascination with technology and computers goes back to the days of Windows XP. Since then, I have been tinkering with OS, mobile phones, and other things. When I am not working on anything, you will find me enjoying video games on some Discord server.