topic Re: Nest Learning thermostat e79 after power outage in Nest Thermostats

Nest Learning thermostat e79 after power outage

jfranks — Sat, 19 Aug 2023 22:57:30 GMT

We've got two Nest Learning thermostats. Due to recent thunderstorm activity we've had brief power outages.

This causes the Nest thermostat to get an E79 error, no power on C. Problem is Nest doesn't recheck power after it's come back on. Only way to get it to recheck is unplug thermostat and plug it back in.

This is a software error in that no one thought about intermittent power problems. This can and probably has caused many expensive service calls for a problem an HVAC tech cannot fix.

Re: Nest Learning thermostat e79 after power outage

David_K — Sun, 20 Aug 2023 16:18:46 GMT

This is great feedback that I'd encourage you to also send directly to Google. You will not receive a response, unless Google need more details from you, however the team are still reading the feedback.

Depending on frequency and length of outage, I have seen other users look at investing in a UPS system so their thermostat and HVAC system remains online during power outages.

Re: Nest Learning thermostat e79 after power outage

jfranks — Sun, 20 Aug 2023 17:21:25 GMT

After talking with support and then escalating to 2nd level support and getting nowhere they did recommend the feedback site you mentioned. This should be a simple problem for them to fix unless the Nest thermostat has some design flaw that prevents a recheck of power after an interuption. Thanks for the reply.