Embedded Nest Thermostat isn’t working (Easy fix!)


Do you see a “Delayed” message on your Nest thermostat? Is it causing heating and cooling problems in your home? You can fix it in two ways.

The first is simple, but it will have to be repeated in the future. Although it is more complex, the second will resolve your problem permanently.

Nest thermostat “Delayed”

Your Nest thermostat will display a “Delayed” message that indicates low power. You can temporarily fix the problem by taking off the Nest thermostat display, plugging it into a USB port, and charging it for two hours. You will need to connect a Common wire (C) to your Nest and furnace for a longer-term fix.

What is the reason for the Nest thermostat’s “Delayed” message?

Newer Nest thermostat models (Learning & E) have rechargeable lithium-ion battery inside. These are backup batteries, nothing more.

The Nest backup batteries can kick in to save your Nest settings and data in the event of power outages.

These rechargeable batteries can’t be replaced. The original Nest used AAA alkaline batteries, which you could take out and replace with newer ones.

The batteries on the newer models are not easily accessible. To gain access, you would need to take apart your Nest piece by piece.

Your Nest will most likely malfunction when the rechargeable batteries run out.

This is evident in the “Delayed” message you are seeing right now.

Charge your Nest for a short term fix

There is an easy fix for the problem that will make your Nest thermostat work again and solve the “Delayed” error.

You only need to charge your Nest.

Start by removing the Nest thermostat display. You will find a USB port at the top of the device if you turn it around.

The model of Nest you have will determine which type of USB charging cable you need.

To start charging your Nest, plug it into a wall outlet (or the USB port on your laptop).

As this is a sign that the Nest is charging successfully, make sure it blinks red.

Your thermostat will take about 30 minutes to charge. It will take up to 2 hours to charge a fully charged battery.

Here is a review of USB charging compatibility.

Once your Nest has finished charging, you can connect it to your wall. The battery will eventually run out and you will need to recharge it again.

For a permanent solution, continue reading.

Fix for long term – Connect C wire to Nest or furnace

The Nest draws a very small amount of power from the cooling or heating wires for most Nest setups. This power is enough to keep the Nest on and running all day.

Sometimes, however, the Nest’s heating or cooling wires may not be sufficient power. You will need a Common wire (or “C wire”) in these cases.

Before we begin, please go to Settings on your Nest then scroll down to Equipment.

Your Nest will display live information about which wires it detects. The yellow wire represents your cooling, the white wire is heat, and green is fan. Red is power.

You’re looking at the blue Common wire that plugs into “C”. This Common wire will draw a small amount of low-voltage power from your furnace to charge your Nest.

If there isn’t a blue Common Wire on the Nest display, then you will want to continue reading.

1 First, turn off your Nest thermostat’s circuit breaker. Next, unplug your furnace. All power should be turned off

2) Next, remove the Nest display case and look at the wires. All wires will be connected except one. It might take some digging to locate it but I believe there may be a blue Common wire in there

3) Once the Common wire is located and confirmed to be present, it’s ready to go to furnace.

4)You’ll need to locate the motherboard inside the furnace. To access the motherboard, you might need to remove a panel of metal from the furnace. You will likely need to remove some screws first.

5)You’ll likely see two main wires when you look inside your furnace’s low-voltage wires. The main wire that runs from the furnace has two off-shooting cables, while the other wire has five off-shooting cables.

6) Leave the main wire and 2 of the off-shooting cables alone. This wire connects to the outside AC unit, but it is not the one we want.

7) Our Nest thermostat wire is the other main wire that has 5 off-shooting cables. One of the 5 off-shooting cables is be blue, and it is not connected. This is your Common wire. That’s your Common wire. Connect it to the motherboard, where it says “Com”.

8) It might be that there is already a wire connecting to “Comm”. It can handle two wires without any problem.

9) Keep the Nest and furnace turned off. Return to the Nest, pull out the common wire blue and connect it with the “C” port.

10) Now, turn on the furnace and the Nest. Go to Settings, then scroll down to Equipment to replace the nest display cover. Verify that the blue wire from your Nest is visible.

11) Done! Your Nest should receive a steady stream power now, and you shouldn’t see the Delayed error ever again.

Common problems that a cable can fix

You may still be skeptical about adding a “Delayed” C wire to fix the error message permanently. Here are five other issues that a C-wire can fix:

Your system is making unusual noises, such as clicking, clicking, clicking, or thumping. This could be due to your system switching on and off quickly.

  • Heating and cooling are always on and will not turn off
  • In a very short time, heating or cooling is repeatedly turned on and off
  • The fan on the system fan is either always running or doesn’t turn off
  • In a very short time, the system fan will turn on and off several times.
  • Nest thermostats perform best when they have consistent power. A C wire is the only way to ensure consistent power delivery.

Support for Nest Customers

Contacting a Nest Pro is the best way to resolve power problems if you aren’t sure or comfortable with fixing it.

They will diagnose and fix any problems that may arise with your thermostat installation.

They can also attach a C-wire or an accessory to a C-wire, such as a Nest Power, if necessary.



It’s possible that your Nest thermostat is showing a “Delayed” message. This means that your Nest battery life has run out

Two solutions are available

This is temporary. It involves taking out the Nest display case, and then plugging it in to a USB charger. The full recharge of your Nest can take up 2 hours.

However, after a while, the Nest battery will stop working and you will need to recharge it.

You can also connect the blue Common wire from your Nest to your furnace for a permanent solution.


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