AC Thermostat Keeps Resetting To 85

AC Thermostat Keeps Resetting To 85—What to Do?

You might not notice that the thermostat has been reset until you notice that your house has suddenly become unexpectedly warm. If the thermostat continues to rise to 85 degrees Fahrenheit, a problem with the device must be investigated. We investigated the most common causes and will discuss them in this post. The following are the reasons why the thermostat keeps resetting to 85 degrees:

  • You have set the thermostat to 85 degrees.
  • The battery is out or is about to die.
  • A thermostat fuse has blown.
  • The thermostat has a wiring problem.

In minutes, you might be able to repair the thermostat that keeps resetting. We require the assistance of an experienced HVAC technician because the problem is so complex. Read on to learn about the various scenarios that can cause this issue and when to contact a professional.

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Possible Reasons Thermostat Keeps Resetting To 85 Degrees Fahrenheit:

Here are some possible reasons we discussed below:

The Thermostat Is Set To 85 Degrees:

The new thermostat could have been pre-programmed to a specific temperature. We may also develop programs without the knowledge of other household members. The thermostat may already be set to 85 degrees if you recently moved into a new home. If it continues to rise to a specific temperature, always check the thermostat settings to see if that is the cause of the reset. In that case, consult the owner’s manual to learn how to reset it to the desired temperature.

Batteries Need To Be Replaced:

If you have a non-programmable thermostat, the issue could be that the battery is old and needs to be replaced. It’s common to believe that you replaced the thermostat battery recently, but the date of the change could be older than you think. Furthermore, not all thermostats include a display that shows when the battery needs to be replaced. In rare cases, the battery may degrade and battery acid may leak into the thermostat, causing additional issues.

The Fuse For The Thermostat Has Blown:

Blown fuses are frequently the cause of constant resets and other issues. When a thermostat blows a fuse, it often fails and resets to a predetermined temperature. Open the thermostat and look for a small transparent cylinder to see if the fuse is blown.

The fuse location varies by thermostat model, but it is usually a colored fuse with a small filament inside. If this filament breaks, the fuse must be replaced with a new one.

You might be able to change the fuse yourself in a matter of minutes. However, if you are unfamiliar with electrical components or have no experience, it is best to leave this task to a professional electrician. Because this is a relatively minor repair, it will not take long to complete.

The Thermostat Has A Wiring Malfunction:

The wiring on an old thermostat may be loose and defective, causing issues with the unit itself. This problem can be difficult to diagnose unless the cable is loose or damaged. The wire may fail, and there will be no continuity. In the latter case, you will need to contact your HVAC technician or electrician to replace the wiring or thermostat if necessary.

Why Is The Thermostat Constantly Resetting?

If the thermostat continues to reset itself, it may need to be reprogrammed, the battery may be faulty, the wiring may be faulty, or the fuse may be blown. It is best to resolve these issues before calling a technician to save money on repairs.

How do I know If My Thermostat Is Damaged?

Thermostats indicate that they need to be replaced when they do. The most common are as follows:

Hvac System Turns On And Off Repeatedly:

The thermostat’s primary function is to communicate with the HVAC system. The thermostat may malfunction if the air conditioner repeatedly turns on and off. It is frequently caused by wire damage, fraying, or a faulty battery. Inspecting the thermostat as soon as possible is best to avoid further damage. Before contacting a technician, you can also troubleshoot.

Incorrect Temperature Measurement:

Inconsistent temperature readings on thermostats indicate that something is wrong. If the thermostat starts recording incorrect temperatures, try resetting it and replacing the battery. If none of these solutions work, contact your technician. The thermostat wiring may be faulty or must be replaced entirely.

The Temperature Is Constantly Changing:

A damaged thermostat has difficulty maintaining correct temperature settings. It may abruptly change and fail to reach the proper temperature after programming. Reprogramming the thermostat and resetting it with a circuit breaker are two options. If the issue persists, it is best to call a technician.

The Hvac System Is Short Cycling:

Recycling entails turning on and off the HVAC system more quickly than is necessary. For example, if the thermostat shuts off after 5 minutes and comes back after 2 minutes, you may have a short cycle problem. Short cycles can also be caused by faulty wiring, but they are more commonly caused by the thermostat operating normally.

Why Does The Temperature Keep Dropping?

If your thermostat is having trouble maintaining the proper temperature, it may need to be calibrated. The thermostat may be set to a pre-programmed temperature and needs to be reset. For instructions on recalibrating the thermostat, consult the owner’s manual.

Finally, the thermostat may be broken or outdated and should be replaced. If your thermostat is more than ten years old and showing signs of sudden failure, we recommend having an HVAC technician inspect it.

How Do I Reset The Thermostat On My Air Conditioner?

There are two ways to reset the thermostat. You can reset the thermostat by pressing the reset button on the thermostat itself. You can also manually reset it using the fuse box. To do this, locate your HVAC system’s circuit breaker and controller.

To begin, ensure that the HVAC system is turned off. Then locate the HVAC system control label and shut off the circuit breaker. Then, after 30-40 seconds, slide it back into place. Then restart the HVAC system.

When Should I Reset The Thermostat?

You must install a thermostat if you have a power outage at home or need to troubleshoot problems with your HVAC system. If your device was pre-programmed, you might need to reprogram it.

Also check: Air Conditioner Outside Unit Freezing Up – What Could Be Wrong?


Now you know why your AC keeps resetting to 85 degrees and how to solve this problem. We hope that this article help you to solve this problem at your own. Before contacting a specialist, try repairing the thermostat first.


How can I set the temperature to stay the same on my thermostat?

By pressing “Hold,” your thermostat will hold the current setting until you make another adjustment. Just click “Run” when you’re ready to restart your regular schedule to get back to your regular programming. A fantastic example of technological innovation is the programmable thermostat.

Why does my AC constantly read 85 degrees?

The following are a few causes for your thermostat to return to 85 degrees frequently:

  • The temperature on the thermostat is set to 85 degrees.
  • The batteries need to be changed.
  • A fuse in the thermostat has blown.

Why does my air conditioner suddenly change settings?

When there is a significant demand for electricity on the grid, such as on exceptionally hot days, they will act this way—the days when you most need your air conditioner. Your energy provider has raised your thermostat to 78 degrees or possibly even higher on that hot day when you would have expected your home to be at a respectable 75 degrees.

Why won’t my thermostat stay in the position I’ve chosen?

There is unsecured wiring. The thermostat can be scratched, broken, or not level. The heater or air conditioner you have is inadequate for your house. The thermostat is not in the best place.

What causes my thermostat to reset itself so frequently?

This type of thermostat occasionally experiences battery failure and acid leakage. Check to see if changing the batteries resolves the problem with the reset. You should replace your thermostat if it resets and doesn’t have a common wire.


About Author

Mobeen Shahid

Mobeen Shahid

Mobeen Shahid is a Mechanical Engineer with two years of experience in the HVAC industry. His passion is analyzing HVAC issues, and he works relentlessly to devise customized solutions. He has been in the industry long enough to know the ins and outs and ensures that areas are optimally heated, cooled, and ventilated.

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