Get Your System Professionally Maintenanced
Nest Thermostats do need professional maintenance from time to time, much like a car. If your system has issues, it may require professional care to get it back on track and functioning again. Try restarting your Nest Thermostat to see if the problem is remedied but returns after a while of use.
Turn the power to your Nest Thermostat off at the breaker switch in your fuse box. Wait a few minutes for the system to pull down, then turn the power back on. If your system functions correctly at first, but the fault returns after the device has been running for some time, it needs to be professionally serviced.
You can diagnose possible system maintenance issues by disconnecting the Nest thermostat and reconnecting your old thermostat. If your system works correctly, there may be an issue with your wiring or power source. You may need a standard wire or Nest Power Connector to use the Nest Thermostat.
Your plan may need maintenance if your system doesnt work correctly after reinstalling the old thermostat.
Check Nest Thermostat Wiring
This is the first thing you should check if the AC doesnt cool.
Sometimes, the Nest thermostat contains bulk or loose wiring connections underneath.
This can cause damage to your device besides being unable to cool. So make sure the internal wiring is well organized in the Nest.
- First, disconnect your device and make sure there is no power supply. It will save you from getting damaged while wiring.
- Now take the display screen from Nest and check the connection.
- Ensure that the wires are in the right place and doesnt lose any connection.
- After That, replace the screen and turn on the power supply.
- Wait for a minute and start the device to check.
How To Turn Off The Ac On The Nest Thermostat Directly
There are multiple ways to turn off your Nest thermostat. One of them is interacting with the device itself. This method is relatively straightforward and involves you using the screen on your Nest device. Here is how you go about it:
Google Nest Thermostat also offers the option to instead turn on or off the heat or utilize a feature called Heat-Cool, which regulates the temperature in the room according to external weather conditions.
Also Check: Ac Humming Fan Not Spinning
Check Your Ac Drain Pan And Drain Lines
Your AC drain pan will fill with water from condensation over time. The drain lines can get clogged with leaves and dirt, so you will need to flush them.
When the drain pan and drain lines get filled and clogged, your AC wont cool properly. The problem may worsen at night because the temperature drops cause the trapped water to expand or freeze.
The fan will still work, which might make you think that the issue is the Nest thermostats fault.
Here is how to clean your ACs drainage system:
Have Your Utility Company Remove The Electricity

Rochelle Ann G. explained that utility companies install electricity-saving boxes in HVAC systems to control how much power youre using.
If your AC works fine during the day but not at night, this could be the issue.
Electricity is cheaper at nighttime, so people turn on power-consuming appliances then.
At the same time, the energy-saving box will cut out power flowing to your HVAC if it detects high power consumption.
You can find the box near the AC or breaker box. It usually has a couple of red and green flashing LEDs.
If you have this box, find a technician who can safely remove the box. You can call the company that installed your HVAC system and have them do it for you.
Recommended Reading: Best Air Filter For Home Ac
Confirm Your Cooling System
Many owners make mistakes in identifying their cooling system type.
Suppose you have a heat pump system but you set up the wires in conventional rows.
So it is essential to confirm the type of cooling system you have.
For that, you can check the backend of your home device. Those sections include the product label, class, and manufacturing details.
Suppose you are still confused about the type of your cooling system.
Google with the model number and search for detailed information. After the confirmation, relabel the wires according to the compatible setup.
You can take help from the free Nest thermostat compatibility checker.
A Flat Replaceable Batteries
The problem
Some Nest thermostats are equipped with 2 AAA batteries to supplement power if the HVAC systems power is insufficient. These batteries also act as a backup option in the event of a power outage. When theyve become old and dont have a high power charge anymore, it may cause the thermostat to cycle on and off.
The solution
Replace the 2 batteries with identical new ones and the problem might be solved.
To replace the batteries, you have to switch off all electrical power to the thermostat and then plug out the Nest thermostat from the wall. Remove the old batteries from their socket and replace them with 2 new 1.5V AAA alkaline batteries.
Return the Nest thermostat to its position on the wall and turn the power on again. If the batteries have been the problem the thermostat will now not cycle anymore.
If the problem persists, you have to troubleshoot the other categories.
Don’t Miss: Hot Water Heater Wiring Diagram
Insert Your Nest Thermostat Wires In The Correct Terminals
You probably know that your Nest thermostat has several wires hidden within its body. Each wire needs to be inserted into its appropriate terminals for the thermostat to function properly.
So, if your Nest thermostat wont turn on your AC, the wires might have loosened or inserted incorrectly.
Out of all the wires in the Nest thermostat, the RC wire is critical to your ACs operation. So, if your AC isnt turning on, its probably because theres an issue with the RC wire .
To resolve this issue, remove your thermostat from the wall and inspect the wires. Ensure all wires are inserted in the right terminals.
If youre not sure how to check and fix the wires in your thermostat, get an expert to help you with that.
Blown Fuse Inside Air Handler
Another less common reason your Nest cooling isnt working is due to a blown fuse inside your air handler.
Getting at this fuse can be a bit tricky and might require the removal of many screws to get the cover of the air handler off.
Once inside, youll see a circuit that has a handful of fuses.
Fuses are relatively cheap, so if youre not sure which one is blown you can just replace them all.
Don’t Miss: Comfort Zone Heater Not Working
Why My Nest Thermostat Not Cooling To Set Temperature
As mentioned, a poor wiring setup can make the nest thermostat stop cooling.
Sometimes, users labeled wires at the conventional side of the thermostat. In contrast, professionals advised conducting this setup on the heat pump side.
Indeed, this is the first reason why the Nest integrated ac doesnt blow cold air.
- Maybe your thermostat is not cooling due to a power outage.
- Perhaps your nest device is not compatible with AC integration.
- Due to regular use, nest thermostat may experience a technical fault, restart before starting.
- Wrong wire installation in your AC. Maybe there is a lack of connection in the Y1 terminal.
- For longer use nest thermostat batteries may go low.
- Motion sensors in the thermostat may not work properly.
- Your smart device may disconnect Wifi automatically after a while.
- Internal damage in your Nest may cause frequent noises like clicking or thumping.
So above are some common issues with nest thermostats.
Below we discuss how to fix those issues that create trouble in the devices.
How To Turn Off The Ac On A Nest From An Echo
Another way to control your Google Nest Thermostat is by using your Amazon Echo and Alexa. You will need to ensure that these two devices are correctly set up and linked. But once they are, there is a range of Nest devices you can control while you are out or at home. Here are the steps on how you go about turning off the AC on a Nest from an Echo:
You May Like: Ac Won’t Stop Running
The Wiring Is Incorrect Or Damaged
Before checking the wiring on your Nest, turn off the power to your HVAC system at the circuit breaker panel or fuse box.
- Remove Nest from the wall to expose the wires.
- Ensure that all the wires are in their correct terminals with the connector tabs pressed firmly down.
- Remove one wire at a time from their terminals, checking for corrosion.
- Reinsert the wires, making sure to press the tabs firmly back in place.
- Restore power to the HVAC system by turning on the breaker.
- Replace Nest back into the wall and wait for it to fully power on.
Try Activating The Cooling Mode From The Nest App

Activating the Cooling mode from the Nest app will help you turn on your AC from your Nest thermostat.
Here are the steps to activate the Cooling mode from the Nest App:
You May Like: Hot Water Heater On Demand
Regardless Of The Culprit Try Restarting And/or Resetting Your Nest
Even if you arent able to pinpoint the problem, resetting and/or restarting the Nest thermostat may be the only thing needed to fix the thermostat.
does a great job of explaining the steps involved in restarting and resetting a Nest. Remember that a factory reset will lose all of your device settings, so only try this if you have exhausted other options.
Solution #3 Power Cycle Problematic Ac
Instead of only fixing your thermostat, you should also pay attention to any problems that the AC itself has.
If everything is okay with the Nest thermostat, then the problem youre having is most likely with the AC.
We will want you to power cycle the AC in order to fix the issue and heres how to do it:
Note: Ensure that by the time youre reconnecting the AC, your thermostat is running and you can test whether the issue is solved.
Read Also: Window Ac Unit Not Cooling
How To Check Your Nest Batterys Status
Go to settings, and then scroll to technical info. Check the power settings. Here you will come across various settings, but the most important ones are the battery level and lin voltage.
If your battery level is above 3.6V, your battery is in good shape. The line level should ideally be above 20 mA. If the line voltage level is below 20 mA, then you will have low power issues.
The Thermostat Frequently Disconnects From Wifi
Your Nest Thermostat is likely disconnecting from the WiFi because its battery level cannot support its smart functions.
If you notice your smartphone constantly attempting to reconnect with your WiFi network, it could be because of the following reasons:
- Your WiFi is not working. Check your WiFis status using other devices to confirm if it is on or not. If you have WiFi on other devices, then it is a sign your thermostat has a problem.
- There might be a problem with the Nest service. When this happens, you might see a message to this effect on the Nest app. In this case, youll have to wait until service resumes.
- Your thermostat has a battery problem. This is often associated with the absence of the C wire.
Also Check: How To Tell If Water Heater Is Gas Or Electric
Remove The Switch Inspect And Clean It
Once you’ve located the condensation overflow switch, lift up on it and remove it from the PVC pipe, then thoroughly wipe it clean using a paper towel. You can use a few drops of soap in water if necessary.
The condensation line overflow switch should have a small float at its base, which you should be able to easily move up and down. If it does not operate in an easy manner, you may need to have a technician come and replace the switch.
Place it aside and, using a flashlight, look inside the drain pipe. Inspect the pipe for any buildup of mold or dirt that could be causing the drain line to back up.
Why Nest Thermostat Isnt Turning On Air Conditioner Unit How To Fix
If your Nest Thermostat isnât turning on your AC unit, there could be a few reasons why. Maybe the AC unit is turned off at the breaker, the AC unit isnât receiving power, or the Nest Thermostat itself needs to be reset.
If the AC unit is turned off at the breaker, simply flip the switch to the ON position. If the AC unit isnât receiving power, check to make sure that the plug is inserted firmly into the outlet and that there arenât any loose wires. Finally, if you need to reset your Nest Thermostat, just press and hold the button for ten seconds.
With these easy steps, you should be able to get your AC unit up and running in no time!
Don’t Miss: Power Vent Water Heater 50 Gallon
Blinking Green Light And Lack Of Response
A blinking light indicates a software update in most cases. While this should only last a few minutes, if you notice it lasting longer, there’s a chance the system’s control board froze.
Try disconnecting the Nest Thermostat from the base and restarting the system. With programmable thermostats, technical difficulties are to be expected with software.
Guide To Troubleshooting Your Nest Thermostat

When it comes to smart thermostats, Nest Thermostats are top of the line compared to any HVAC system. From all generations of the Nest Learning Thermostat to the Nest Thermostat E, outstanding performance is standard. However, even a smart thermostat won’t last forever.
In this guide, we’ll troubleshoot common problems with smart thermostats so you can figure out what’s going on with your HVAC system.
Don’t Miss: Best Heated Socks For Skiing
Check Your Nest Thermostat Wires
The Nest thermostat has several wires within its body. For the thermostat to work properly, every wire has to be inserted correctly into its terminal. Some of these wires might have loosened over time. If the thermostat has never put on the air conditioner since installation, the wires might have been inserted incorrectly.
For AC activation, the most important wire to be without any fault is the RC wire. This wire might be loosened, burned or inserted in the wrong terminal.
To check the wiring, terminals and connections, you have to remove the thermostat from the wall for inspection especially the RC wire. Ensure that the wires are inserted correctly and not damaged. The RC terminal has to be connected to activate the cooling function of your HVAC system.
If your thermostat has no RC or RH terminals but only one terminal marked with an R, the systems R wire should be connected to the R terminal. This R terminal is the 24-volt hot terminal. The power originates at the 24-volt transformer and supplies power to the thermostat and then passes power to the devices, like your AC.
Thus, when you inspect the wiring and connections, check all the thermostats terminals.
The Most Common Problems With The Nest Thermostat Heating And Cooling System
Common Nest Thermostat problems can range from faulty wiring to a clogged air filter. Sometimes it’s as simple as the Nest Thermostat being unable to connect to the WiFi. While you can, and should, contact Nest support with any problems, first try to troubleshoot yourself.
As you read through the list of common troubleshooting issues with Nest devices, always exercise caution while working on home repairs. For example, ensure that the breakers are off before you begin tampering with the wires to ensure you don’t receive a shock.
Recommended Reading: Water Not Getting Hot Gas Water Heater
Why Your Nest Thermostat Isnt Turning On The A/c
There are multiple reasons as to why your Nest Thermostat isnt turning on the A/C. Luckily, most of them are easy fixes and dont require a ton of work.
Here are six reasons why your Nest thermostat isnt turning on the A/C:
- Incorrect thermostat wiring
- Not getting enough power supply
- Wi-Fi location issues
- Continuous running of the HVAC system
- Thermostat battery at the end of its lifespan