Why is Nest Thermostat Off but Heating On? Easy Fix

Is your Nest thermostat off but heating on, and you are wondering what is wrong with it?

Of course, you expect that when you power off the system, everything should stop working.

Read below to understand why your Nest thermostat behaves this way and how you can fix it.

When Nest thermostat is off but heating on, it can be due to the wrongly inserted wires into the system. Check and insert them correctly and remember to conduct maintenance regularly on your system.

Why Does My Nest Heating Keep Coming On

Several reasons may cause your thermostat heat to keep coming on. Check below for some of them.

• Your system lacks maintenance.
• The wires are not correctly inserted.
• Your thermostat is not in the correct position.
• Your thermostat system is outdated.
• You have compatibility issues.

Note: when your thermostat has a heating problem, it is always wise to have an expert check it for you.

The moment you realize this problem, kindly do not take chances with it.

Now, let us get down to troubleshooting methods and get your thermostat working again.

How to Fix Nest Thermostat Off but Heating on Issue

Below are several fixing methods you can apply on your Nest thermostat if you power it off, but heating is still on.

Do not tire when one fails to work. Attempt all until your system works normally again.

Fix #1: Check If Your System Needs Maintenance

Like every other electrical gadget, your thermostat needs regular maintenance for it to work correctly. 

You can know that your system needs maintenance when you restart it. It begins working normally, and then the issue comes back after a while.

To restart it:

1. Turn off the breaker, and the system switch powers.
2. Allow the system some minutes to rest, then turn it back on.
3. Check if the thermostat is working normally.

Another way to check if it needs maintenance is by removing your Nest thermostat and installing your older one.

Test if the system is operating correctly. If the system is behaving the same way as your older thermostat, then it needs maintenance.

Your local HVAC system pro can diagnose and fix the issue for you.

Fix #2: Adjust the Temperature Setting

The heating system may fail to turn off. Hence, the thermostat will deliver heat even when the thermostat is off.

You can try setting the thermostat to its lowest temperature. Wait for around five minutes to see if it will adjust itself to a higher temperature.

If the thermostat stops heating, then the problem is in your thermostat settings.

You will need to reset your Nest thermostat and see if the problem resolves. If not, kindly proceed to fix number three.

Fix #3: Check the Position of Your Thermostat

You cannot place your thermostat anywhere and expect it to work appropriately. There are specific positions that will give your thermostat a hard time.

You are supposed to place your thermostat in an interior wall that is about chest height. The place should be far from drafts and where unusual temperature conditions will not affect it.

Some locations you can avoid placing your thermostat include:

• A wall outside the room.
• In direct sunlight.
• Near a kitchen or boiler wall.
• Next to air ducts or concealed pipes.
• Behind furniture, in an alcove, or behind a door.
• In an entry hallway.                           
• In a bathroom.
• In a line or above an airflow path from a cooling or heating air supply register

Some of the recommended locations for a thermostat include:

1. In a dining or living room.
2. A position where your thermostat will have natural air circulation.

Fix #4: Check Thermostat Wiring

If your furnace system is operating by forced hot or warm air, heating will run continuously even if the thermostat is off.

Check the two switches on the system that make the blower fan to operate throughout even though the air is not heating up.

Either the thermostat switch or the limit switch can cause the blower fan to run continuously. You can put these two switches at fan off.

You can also separate the thermostat wires from the heating system. Remove the two thermostat wires at the main control for the heating system.

To quickly identify them, these wires are white and red. And you will see them connected to terminals T1 and T2 in the controller.

The issue should stop once you do this. Hence, you will know that the problem is the wire connections.

Fix #5: Check System Compatibility

You may have a system incompatibility if your Nest thermostat heats while it is off.

Even though Nest thermostats work well with most 24V thermostats systems, some systems from some manufacturers will not be compatible with your Nest.

Some systems may need the Nest power connector or a C wire connected for them to be compatible.

When setting up the Nest thermostat, the Nest app will help you understand the systems that your thermostat is compatible with.

So, if you ignore that direction, your thermostat will always have the same problem.

Also, you can check your system’s compatibility using the Nest thermostat compatibility checker.

Fix #6: Check the C Connector

If the wire in the C connector is not correctly inserted into the unit, it can cause your thermostat to misbehave.

Pull off the display and confirm if, first, the wire is available in the connector or not. And if it is there, is it correctly inserted?

Check if all the wires are in their correct connectors. You can confirm it by checking the diagram of your old thermostat wiring when you were installing.

If there is no wire in the C connector, check for one in your system’s board, then connect it to your thermostat.

Ensure that you turn off the power to your house at the breaker, the fuse box, or the system switch. Hence, you will protect the system and yourself, too, from the high voltage wire.

If you are not sure about the procedure to connect the wires, do not hesitate to call a pro to do it for you. If the strange heating behavior is still there, let us proceed to the next fixing method.

Fix #7: Install A Nest Power Connector to The Thermostat

A Nest power connector is a power device that is relatively affordable and simpler than a C wire.

You will need an expert to connect it for you, then check if the issue is resolved.

Fix #8: Get the Latest Version of Your Nest Thermostat

If your Nest thermostat runs on old firmware, it will fail to deliver correctly.

You will have weird issues like the heating system is on while the thermostat is off. 

You need to update the thermostat to avoid such issues.

The procedure below is for a Nest thermostat. You do not need to update a Nest Learning thermostat 3^rd Generation or a Nest thermostat E.

1. Turn your thermostat to the Off mode.
2. Select Settings on your thermostat followed by Version
3. Click Update

Ensure you get a 1.1 version or above.

Fix #9: Contact Google Nest

Have you tried the above troubleshooting steps, but none has worked for you? The solution is contacting Google Nest to help you fix your thermostat.

If your device still has a valid warranty, the company can fix it for you. If it fails, they can give you a newer one, which will not give you a hard time.

If your thermostat is off, but heating is on, your thermostat is wrongly placed, or the system lacks maintenance. Check if the wires are correctly inserted into the thermostat and ensure that you place your thermostat in a place free of heat or direct sunlight.

Read Next: Why is My Nest Thermostat Not Heating?

Final Thoughts

For a nest thermostat off but heating on issue, you can now relax because the above tips have you covered.

At least one or two methods should work. If not, do not hesitate to call the experts to check your Nest thermostat for you.