I bought into the whole Nest thermostat craze and have paid the price. Converted my heating and AC thermostat over to a Nest Learning in April 2021. Heating worked, then I transitioned to AC for summer. In early Oct, I got my heating system ready for winter and discovered infamous N72 error (doesn't detect Rh wire). Taco box on furnace just keeps clicking. Call heating maintenance company and the first thing the tech said was "you have a Nest thermostat". There is no problem with the heating system, its all with the Nest Learning Thermostat. Other have the same problem, yet all the millennial help desk (insert derogatory term here) do from their basements is treat you like an idiot. Enzo, Madison, Caitlin - useless. Google knows the problem, yet they won't equip these folks to help. "Does your house have power?" Give me a break. DO NOT BUY THEIR JUNK. You will end up like me. I need to spend money to get a new thermostat tonight or go cold. I'm on day 23 of their BS.
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 & N72 error. You will see other posts about this across the web. Called 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). Notified Google and then sent me new baseplate (arrived last night and installed - no fix. Same exact issues). Contacted them again this morning and just went through 2 hours of painful chat troubleshooting with totally useless reps (Madison and then Enzo). If you get them, stop the chat, pull the Nest out of your house and get another brand. I'm done with having a teenager in their basement ask me if my house is powered and calling it support/troubleshooting.
Ask for escalation to a tier 2 (I think) level of support and do it over the phone. Had a 1 hour+ session last night with Support Tech named Michael. Understands the issue and very competent. We got the heating unit to start ( thermostat talking to system) and are pretty sure we identified the problem (need isolation relay on heating system to provide enough voltage to thermostat).
Mine is a Taco 504 4 zone relay. My boiler manual mentions the need for an isolation relay coil if using 3 thermostats. Google Rep felt that it was needed to provide voltage to the thermostat. I bought a Honeywell 5-2 Programmable thermostat ($22) at Home Depot earlier today and swapped it with the Nest. Both AC and heat are 👍. This buys me time to research the isolation relay coil with my heating maintenance contractor.
If you are dealing with the N72 error code and can't get your heating system to operate (as the cold weather sets in), then please respond to my post. Google is pretending that it doesn't exist. They humiliate you by asking you to perform useless troubleshooting tasks that they know don't work, only to stop communicating with you about the problem. Here's my story;
Purchased Nest Learning to control both Heat (boiler) and AC (older system) in New England. Installed 1 Apr 21. Used heat and AC through mid June before transitioning to summer AC. While getting ready for winter on 6 Oct 21, turned on heat and controller in TACO box (interface between thermostats and boiler) just kept clicking. Called HVAC Co for PM and troubleshooting. No issue with boiler. Nest giving N72 error - no power to heat Rh wire (not true). Tech bypassed thermostat and started boiler. Contacted Nest - given unbelievable run around, including sending part that they knew wouldn't fix it. Contacted again today (10-29) and given same run around. Won't acknowledge problem or propose solution. Blames me. This is a common problem and not unique. Save the hassle and buy another brand. You can thank me later.
We are the customers. They treat us like crap. Complain now! If you just give up and buy another thermostat without making Google feel the pain, then you are just passing the buck until another unsuspecting person buys this crap and experiences the same problem. HOLD THESE CLOWNS ACCOUNTABLE!!!!
Same problem. They denied any issue and told me I should hire a technician to check wiring. I explained that in an engineer and wires are fine. I could jump my Rh and W and heat comes on. I found an old issue in the forum with the same problem caused my a firmware update. The person eventually hung up on me after I asked to escalate. Very frustrated.
I just finished a 1 hour + session (phone) with a second tier support person named Michael. He was excellent. He was referencing manuals for my boiler and the zone box where all the thermostats “talk” to the boiler. I need to add an isolation relay coil so the Nest Learning Thermostat can get enough power. This was consistent with what my Heating System Tech said. So, it’s not the baseplate or the thermostat. We were able to disconnect the ac and get the thermostat to turn on the heat.
Were they able to explain why the heat worked last season and not this season with the same thermostat? I tried swapping my Rh - Rc and Y - W and no luck. Doesn't make sense as nothing changed since the last hearing season and it works by putting a jumper between the Rh and W wires. It's basically a simple normal open circuit that gets closed to call for heat
Temporarily. Thermostat battery was dead by morning. Can’t tell when it happened. Went to Home Depot and bought a Honeywell 5-2 programmable thermostat (not smart or WIFI). Inserted wires (with exception of C common wire) and started it up. Both AC and heat work fine. This will get me thru until I determine if I’ll add an isolation relay coil to my heat (to provide voltage).
I’m having the same exact issue as you are however I’ve had the thermostat installed for a few years and it is a new issue this year after working fine. I installed the thermostat 3 years ago and it worked for a while before it started losing power. I ran a common from the air handler and it solved the issue and all has been well until this year. Not sure I have the patience for this trouble shooting but I’ve got 3 nest thermostats and the doorbell and I’d prefer not to throw it all away…
I've spent the last two weeks in limbo with this same issue. I can't get their attention so I am contacting the FTC. My problem is, my heat pump only warms until its 40 degrees. Then my auxiliary heat kicks in. Emergency heat which is natural gas will only operate from the app. The thermostat doesn't freakin' work! HVAC said the connection wire was bad. SO now Google wants me to: buy a new one @full retail through their store, pay an HVAC guy to install the new one, and send the old one back within 21 days OF THEM SHIPPING THE FIRST ONE, and maybe I will get my credits back.
Here's what I think the scheme is: Google want to talk to you about it until your warranty period runs out then you get nothing. I have completely lost respect for this company. They have a few TRILLION dollars in assets and you think they could spare a few replacements?
I did warn them, on a recorded line, that they would be held professional AND PERSONALLY responsible if any malfunction causes damage to my home.
They used to respond on these forums. Seems they don’t care anymore. I moved a different thermostat upstairs and it runs great; Nest E. It’s so stupid the Nest E works fine but the more expensive Nest can’t turn the heat on. Also I don’t have patience for them to try to blame the wiring or the HVAC system when I know **bleep** well it’s their thermostat/software that is an issue.
Yep. Nest 3rd gen is absolutely useless. Will not stay connected to my wifi, powers off all the time, turns my heater on and off constantly for short intervals of time because the temp sensor can’t make up its mind and constantly tells me the time and date is wrong. $250 for a retarded circle that can’t turn a simple gas heater on in my garage to keep my home theater and pc warm during the winter months. The best part is… I punched the thing off of my wall and it started working for a couple of hours lol. Oh and let’s not forget that they will not honor the warranty if a “NEST PRO” doesn’t install the stupid thing. Because it requires so much skill to correctly match up a few labeled wires, right?
Right there with you wasted four hours of my life last night trying to connect something that seems so easy to connect it even had a ZIP Code pre-installed for me so that tells me that some other idiot bought one returned it to Amazon and Amazon sold it to me guess what Amazon said forget the refund will refund your money just throw or give away the item I guess I’ll take a Wi-Fi hemorrhoid cure before I will invest in a Wi-Fi thermostat again and why do we need one exactly? I kind of missed a mercury bulb floating back-and-forth. This technology craze is going to be the death of us all. I’m ready for legal pads and clipboards. A nice Mont blanc pen might be a welcome addition. No more tech for me I’m done and I’m only 59
I do not understand this device from the core. We have this thermostat in our office. Every day I come to the office and set the temperature to 75 deg F. First it will swing waaaaay down to 68 and I'm like for heavens sake now stop. Thankfully it will stop. One hour, 2 hours, it is still stopped and I'm sweating. Look at the temperature, it is going above 85 degrees. What in the freakin world is this piece of hardware doing? 75 degrees mean 75 degrees .. not 68 degrees and definitely not 85 degrees. Google has produced an ultimate piece of junk here!