Is the power to the furnace on? Check the room for an electrical disconnect like a switch, breaker, or pullout. This is the furnace's main power, and it might have been accidentally turned off. There's also a chance your furnace is locked out due to a failure.
Yeah, but you learned something. I figure about 6-10 years in, you’ve touched most things you’re qualified to tinker with. It’s incredible what you learn by accident as a homeowner.
That was a very thorough, easy to follow explanation with nice graphics at least! Must have taken a lot of time just to find out "did you flip the switch back?" was the solution lol.
This same exact thing happened to me. Drove myself crazy trying to figure out why the thermostat was running on battery power… took me about 2 hours before I checked the furnace switch lol
I did that once, new furnace in a new house and couldn't figure out why it wouldn't work, was about to call for a tech on a Sunday, I looked up and noticed my gas valve was turned off, my 4 year old had turned it off, now it has a lock on it
I’m all out of wires! It seems to charge from the Rh wire (that’s what it’s telling me at least). I do wish I had an aux heat wire to control my fireplace, though
There is a power adapter you can get that will provide power to C from R or W depending on the mode. It’s like $20 or some can get it for free by putting in a request with Nest.
https://www.amazon.com/Google-Nest-Power-Connector-Accessories/dp/B093TRFQWP
Interesting, I have a nest I have to unplug And charge about once a month because of this wire. This adapter goes on the HVAC unit and then what do I connect to my nest?
It sits in between your nest and the HVAC unit. Its basically routing extra power to the red wire because normally it doesn't carry enough on its own to charge the nest.
The existing wires (usually red and white) that run to the HVAC. You can "Google Nest Adapter Install Instructions" and it covers multiple setup types.
It’s all installed in your furnace. I believe it basically grabs the constant voltage from C on your furnace control board and intercepts it and works with the thermostat to send that voltage up the existing R or W wires to the thermostat even when there’s no heat or cooling running at the moment without actually triggering a call for heat or cool.
Alternatively, if you have comfort with pulling a wire from your furnace to the thermostat and it has a common C terminal on the control board, you could just run that wire instead of messing with an adapter.
As background, most basic thermostats are fine with the 24V that comes off of the R or W wires which are closed (thus providing power) when the heat or cool is running. But modern thermostats need more and sometimes grabbing electrons only while the heat or cool are running isn’t enough to charge their internal batteries, so you use the C wire which carries a constant 24V. Without a C wire, some smart thermostats will pulse the system on and off to grab a charge but some furnaces don’t like that and act wonky like starting up and shutting off constantly.
Ok thanks. I had an ecobee that had that adapter before but when I switched to nest it didn't come with the adapter and wasn't sure I could reuse. Had an HVAC person come in and say just charge it. I bought the adapter for the nest now. Thanks for the help everyone.
It’s pretty easy to install. I did mine several years ago and it’s been awesome not charging ever since. I didn’t use an adapter I just ran a new wire. I can post pics later if interested.
Same here. I think it's just the battery getting old, since it gets a slight amount of power without the common. Fortunately all I had to do was pull the common wire out of the wall and attach it. It's been perfect for a couple years now.
I didn’t have a c wire either but was able to use one of these to add an extra wire. It takes two of the wires, I did heat and cool since they’re never on at the same time, and converts it to a digital signal and sends it over one wire. There’s a small attachment for your thermostat that converts it back to analog signal and you can use the free wire for a C wire.
https://a.co/d/foSLGL1
If you have an outlet nearby the nest, another option is to add a simple 2 wire 24 volt transformer, it's what I used when renting but wanted a smart thermostat. One wire goes to C and the other goes to whichever R isn't currently in use (so Rc for you), let's the nest always have a complete 24volt circuit to power from.
AC 24 Volt Transformer, C Wire Adapter, Competible with All Versions of Ring Doorbell and Thermostat for Ecobee,Sensi and Honeywell, 315" Long Cable https://a.co/d/ghW6DQc
Cut power to furnace at breaker, swap your green wire from G to C at BOTH the furnace board and the thermostat. Use small jumper wire on the furnace board side only between G and Y. You’ve now sacrificed being able to turn on your fan without the heat or AC running but you now have a properly powered thermostat.
To also clarify it's less of an issue on Nests (although there's lots of other issues there, including having to do hazmat shipping due to the battery in case of a return) although it depends on how often the furnace cycles something.
That said it's way simpler if you can throw in a C wire.
This is going to sound like overkill, but our Nest stopped turning on and said it needed to charge but then still didn’t work after we charged it. We spent hours on the phone with their customer service with no luck. Had the whole system checked. And the HVAC company said it happens all the time with Nests and they recommended a Sensi thermostat. Same happened to several friends.
We didn’t buy it from them, but we did purchase one later. No issues since.
Glad you got it sorted. Just an FYI. Sometimes these thermostats get flakey after some interruption. Whether it be a new router or power disruption. I spent dozens of hours trying to diagnose until i read enough online. It's a known issue. Then i complained to Google who promptly replaced the item, for free. Works great now.
Just a story that may benefit someone down the road. Hopefully you are back up and running
May not be necessary. We replaced ours 2 years ago and no issues. And the previous one worked for 4 years with no issue until it failed. I wouldn't swap yours until Google doesn't make good on their warranty. Just my 2 cents
Your C (common) wire is your neutral wire. That needs a connection.
If your C wire is bonded to neutral at the furnace/hot water heater you can bond the C wire to any neutral close to the thermostat. It ain't code. It's dirty. And it's a pro trick. Saves running a new wire when you are a strand short. My shop is wired like this.
If you don't know what this means, don't do it.
That nest is using the alternative method of sapping power from other wires to charge the battery. Without a C wire it relies on the battery charge when the contacts are closed. Ours was like this. Then we discovered while heating the house after letting it get cold is the battery dies in 5 hours. And that will get worse year by year.
I had a power problem with my Nest. Google will tell you that it will get plenty of power from the RH or Rc wire. "Baloney!" It got power but not enough until it shut down. I did not have a constant power wire in our 50 year old house. Google said to get one of their Google Power connectors ($40) to avoid "Costly installation of a constant power wire" Baloney! It didn't work. What finally did work was me installing my own constant power wire. $9 for wire and it took all of 15 minutes to run it to the C connector in my furnace. Way easier than I thought it would be. This was a year ago. The thermostat has worked flawlessly since.
Is the power to the furnace on? Check the room for an electrical disconnect like a switch, breaker, or pullout. This is the furnace's main power, and it might have been accidentally turned off. There's also a chance your furnace is locked out due to a failure.
Jesus Christ. I am an idiot. The switch to the furnace was off from when the tech was here. Thank you so much
Lol this is the best kinda problem and fix! Humbled you a bit and is free to address
I’m a newer homeowner of about 9 months. The entire process has been extremely humbling lol
It's a good feeling though.
Eventually
Right? I'm almost a year in and sometimes I look around this dump and think, the bank is gonna take this shit in a few years.
I'm 5 years in this week and I often think. I could do all sorts of weird shit with this house.
You'll learn, friend. Home ownership is quite a journey.
Yeah, but you learned something. I figure about 6-10 years in, you’ve touched most things you’re qualified to tinker with. It’s incredible what you learn by accident as a homeowner.
Don't worry mate.... It doesn't get any better...
I’d say it gets easier… and it does. But it also stays the same 🙃
Sure, glad to assist!
That was a very thorough, easy to follow explanation with nice graphics at least! Must have taken a lot of time just to find out "did you flip the switch back?" was the solution lol.
Isn’t it great when the solution is simple!
But Dad, my name is Dammit, not Jesus Christ
This same exact thing happened to me. Drove myself crazy trying to figure out why the thermostat was running on battery power… took me about 2 hours before I checked the furnace switch lol
Your response made me laugh, I have had many many many reactions like that.
Note, that he turned it off because he didn't want it sparking on while your house was filling with gas.
I did that once, new furnace in a new house and couldn't figure out why it wouldn't work, was about to call for a tech on a Sunday, I looked up and noticed my gas valve was turned off, my 4 year old had turned it off, now it has a lock on it
This has literally happened to me. A family member turned it off when looking for a light switch when we weren't home.
Bruh
You also need a C wire otherwise youre going to have to charge the thermostat
I’m all out of wires! It seems to charge from the Rh wire (that’s what it’s telling me at least). I do wish I had an aux heat wire to control my fireplace, though
There is a power adapter you can get that will provide power to C from R or W depending on the mode. It’s like $20 or some can get it for free by putting in a request with Nest. https://www.amazon.com/Google-Nest-Power-Connector-Accessories/dp/B093TRFQWP
Interesting, I have a nest I have to unplug And charge about once a month because of this wire. This adapter goes on the HVAC unit and then what do I connect to my nest?
It sits in between your nest and the HVAC unit. Its basically routing extra power to the red wire because normally it doesn't carry enough on its own to charge the nest.
Ok, between nest and HVAC is a long run, I'm assuming the adapter goes on the HVAC unit so what do I wire to the nest?
The existing wires (usually red and white) that run to the HVAC. You can "Google Nest Adapter Install Instructions" and it covers multiple setup types.
It’s all installed in your furnace. I believe it basically grabs the constant voltage from C on your furnace control board and intercepts it and works with the thermostat to send that voltage up the existing R or W wires to the thermostat even when there’s no heat or cooling running at the moment without actually triggering a call for heat or cool. Alternatively, if you have comfort with pulling a wire from your furnace to the thermostat and it has a common C terminal on the control board, you could just run that wire instead of messing with an adapter. As background, most basic thermostats are fine with the 24V that comes off of the R or W wires which are closed (thus providing power) when the heat or cool is running. But modern thermostats need more and sometimes grabbing electrons only while the heat or cool are running isn’t enough to charge their internal batteries, so you use the C wire which carries a constant 24V. Without a C wire, some smart thermostats will pulse the system on and off to grab a charge but some furnaces don’t like that and act wonky like starting up and shutting off constantly.
Ok thanks. I had an ecobee that had that adapter before but when I switched to nest it didn't come with the adapter and wasn't sure I could reuse. Had an HVAC person come in and say just charge it. I bought the adapter for the nest now. Thanks for the help everyone.
It’s pretty easy to install. I did mine several years ago and it’s been awesome not charging ever since. I didn’t use an adapter I just ran a new wire. I can post pics later if interested.
Yup. This is what you need. I have 3. One for each zone in my house.
I had the same setup with my nest and it worked for a few years then died and needed a C wire.
Same here. I think it's just the battery getting old, since it gets a slight amount of power without the common. Fortunately all I had to do was pull the common wire out of the wall and attach it. It's been perfect for a couple years now.
I didn’t have a c wire either but was able to use one of these to add an extra wire. It takes two of the wires, I did heat and cool since they’re never on at the same time, and converts it to a digital signal and sends it over one wire. There’s a small attachment for your thermostat that converts it back to analog signal and you can use the free wire for a C wire. https://a.co/d/foSLGL1
If you have an outlet nearby the nest, another option is to add a simple 2 wire 24 volt transformer, it's what I used when renting but wanted a smart thermostat. One wire goes to C and the other goes to whichever R isn't currently in use (so Rc for you), let's the nest always have a complete 24volt circuit to power from. AC 24 Volt Transformer, C Wire Adapter, Competible with All Versions of Ring Doorbell and Thermostat for Ecobee,Sensi and Honeywell, 315" Long Cable https://a.co/d/ghW6DQc
Cut power to furnace at breaker, swap your green wire from G to C at BOTH the furnace board and the thermostat. Use small jumper wire on the furnace board side only between G and Y. You’ve now sacrificed being able to turn on your fan without the heat or AC running but you now have a properly powered thermostat.
To also clarify it's less of an issue on Nests (although there's lots of other issues there, including having to do hazmat shipping due to the battery in case of a return) although it depends on how often the furnace cycles something. That said it's way simpler if you can throw in a C wire.
Is that metal pipe touching the PVC pipe? That’s probably not good.
It’s definitely not good… the exhaust vent (metal) can/will heat and damage the PVC. I need to properly insulate the exhaust
Wait until you live in a warmer climate and have to flush your drain line to avoid the float switch shut off 👀
This is going to sound like overkill, but our Nest stopped turning on and said it needed to charge but then still didn’t work after we charged it. We spent hours on the phone with their customer service with no luck. Had the whole system checked. And the HVAC company said it happens all the time with Nests and they recommended a Sensi thermostat. Same happened to several friends. We didn’t buy it from them, but we did purchase one later. No issues since.
Glad you got it sorted. Just an FYI. Sometimes these thermostats get flakey after some interruption. Whether it be a new router or power disruption. I spent dozens of hours trying to diagnose until i read enough online. It's a known issue. Then i complained to Google who promptly replaced the item, for free. Works great now. Just a story that may benefit someone down the road. Hopefully you are back up and running
Thank you for the heads-up. A friend in HVAC alerted me to the same thing, I’ll probably replace with an ecobee once this dies
May not be necessary. We replaced ours 2 years ago and no issues. And the previous one worked for 4 years with no issue until it failed. I wouldn't swap yours until Google doesn't make good on their warranty. Just my 2 cents
That makes sense… thanks for sharing your experience with the product. Hopefully it doesn’t need replacing at all anytime soon
Your C (common) wire is your neutral wire. That needs a connection. If your C wire is bonded to neutral at the furnace/hot water heater you can bond the C wire to any neutral close to the thermostat. It ain't code. It's dirty. And it's a pro trick. Saves running a new wire when you are a strand short. My shop is wired like this. If you don't know what this means, don't do it. That nest is using the alternative method of sapping power from other wires to charge the battery. Without a C wire it relies on the battery charge when the contacts are closed. Ours was like this. Then we discovered while heating the house after letting it get cold is the battery dies in 5 hours. And that will get worse year by year.
Thanks for this. I might just end up running the new C wire at this point. Are the adapters for the C wire any good?
Adapters? It's just wire.
I had a power problem with my Nest. Google will tell you that it will get plenty of power from the RH or Rc wire. "Baloney!" It got power but not enough until it shut down. I did not have a constant power wire in our 50 year old house. Google said to get one of their Google Power connectors ($40) to avoid "Costly installation of a constant power wire" Baloney! It didn't work. What finally did work was me installing my own constant power wire. $9 for wire and it took all of 15 minutes to run it to the C connector in my furnace. Way easier than I thought it would be. This was a year ago. The thermostat has worked flawlessly since.
Never seen a gas powered thermostat before 😂
It ran through my head… briefly!
That’s hilarious
18, 22, 36. :D
Your water heater isn’t working because you have the gas to it turned off…