AC Thermostat Keeps Resetting To 85—What to Do?

AC Thermostat Keeps Resetting To 85

Until the house abruptly heats up, you might not realize the thermostat has been tampered with. The thermostat should be checked for malfunction if it keeps climbing above 85 degrees Fahrenheit. We looked at the most typical reasons, and we’ll go over them below. The thermostat keeps resetting to 85 degrees has been attributed to the following:

  • You’ve decided to maintain a temperature of 85 degrees.
  • There is no power since the battery has run out.
  • The thermostat has a blown fuse.
  • The thermostat’s wiring is malfunctioning

The thermostat that constantly resetting could be fixed in a matter of minutes. Because this is such a complicated issue, we need to hire a professional HVAC specialist for help. Keep reading to find out what could be triggering this problem and when you should get help.

The thermostat keeps resetting to 85 degrees Fahrenheit; what could be causing this?

Some of the factors we’ve considered below are:

The Thermostat Is Set To 85 Degrees:

We have the thermostat set at 85 degrees. The setting temperature on the new thermostat could have been predetermined. It’s also possible that we’ll create programs in secret, away from the prying eyes of family members. If you just moved into a new house, the temperature may already be set to 85 degrees. Always double-check the thermostat settings to determine if it wasn’t the cause of the reset if the temperature keeps climbing to a certain level. If that’s the case, read the handbook to find out how to change the settings.

Also, Read: How To Keep Nest Thermostat from Changing Temperature?

It’s Time to Get New Batteries:

The problem could be an old battery in a thermostat that doesn’t require programming. It’s easy to fool yourself into thinking you changed the thermostat batteries lately when in fact the swap may have occurred months or even years ago. In addition, the display on some thermostats may not indicate when the battery has to be changed. Thermostat problems can be compounded by the possibility of battery acid leaking into the device.

The Thermostat’s Blown Fuse:

Burnt fuses are a common source of resets and other problems. A blown thermostat fuse usually causes the thermostat to fail and reset to an earlier setting. To check if the thermostat’s fuse has blown, open the device and locate the tiny, see-through cylinder inside.

Different thermostat models have different fuse locations, but typically a colored fuse with a little filament within serves that purpose. A new fuse will need to be installed if this filament ever burns out. In a few minutes, you could try replacing the fuse on your own.

If you lack the knowledge and experience necessary to work with electrical components safely, however, you should probably hire an electrician to do the job for you. Due to the minimal nature of the damage, fixing it won’t take too much time.

There is a Problem With the Thermostat’s Wiring

An outdated thermostat’s wiring could be sloppy or broken, leading to operational difficulties. Unless the cable is loose or damaged, finding the source of the problem can be challenging. There is a risk of interruption if the wire breaks. If the latter is the case, you should call a heating, ventilation, and air conditioning (HVAC) expert or an electrician to install new wiring and a thermostat.

How Come the Thermostat Keeps Resetting Itself?

You may need to reprogram the thermostat, replace the battery, check the wiring, or replace the fuse if it keeps resetting. Fixing these problems yourself can save you money that would otherwise be spent on repairs.

How do I know If My Thermostat Is Damaged?

When a thermostat needs to be replaced, it will give a warning. Here are some of the most typical examples:

Repetitive cycling of the HVAC on/off system:

The thermostat’s principal role is to act as a link between the heating and cooling system. Having the AC cycle on and off frequently could indicate a problem with the thermostat. Damaged or frayed wires or a weak battery are common culprits. If you want to prevent more damage, you should check the thermostat as soon as possible. Troubleshooting is another option to try before calling a technician.

Bad Temperature Readings:

When thermostats give wildly varying temperature readings, you know something is wrong. Try resetting the thermostat and installing a new battery if it begins registering erroneous temps. If you’ve tried everything and still can’t get it fixed, call your professional. There may be a problem with the thermostat’s wiring, or it may need to be changed.

The Weather is Always Fluctuating:

When a thermostat is broken, it can be difficult to keep the house at the desired temperature. After being set to a certain temperature, it could suddenly shift and fail to maintain that setting. You may either re-program the thermostat or reset the circuit breaker to get it working again. Calling a technician is recommended if the problem persists

Reduced HVAC Long-Cycle Times:

To recycle, you must rapidly cycle the air conditioner and heater on and off. You may have a short cycle issue, for instance, if the thermostat turns off after 5 minutes and then turns back on after 2. While defective wiring is a possible source of short cycles, a properly functioning thermostat is more often at blame.

Why Does It Keep Getting Colder?

Your thermostat may need adjustment or calibration if it’s not keeping a consistent temperature in your home. It may be necessary to reset the thermostat to its factory settings. Check the manual that came with the thermostat for information on how to make adjustments. L

ast but not least, it’s possible that the thermostat is faulty or just old and has to be changed. We advise having an HVAC specialist take a look at your thermostat if it’s more than ten years old and showing signs of sudden failure.

How Can I Turn Off the Air Conditioner And Reset The Thermostat?

Two different procedures exist for resetting the thermostat. The thermostat has a reset button that can be used in this situation. The fuse box allows for manual reset as well. Find the circuit breaker and controller for your HVAC system. Turn off the heating, ventilation, and air conditioning system first.

The next step is to turn off the circuit breaker and find the label for the HVAC system controls. Wait 30 to 40 seconds, and then re-insert it. Then, turn the air conditioner back on.

Also, Read: Optimal Temperature To Set Your Heat To In The Winter

At What Point Should I Aim For A Cooler House?

In the event of a power loss or HVAC troubleshooting, a thermostat is an absolute necessity. It may be necessary to re-program your gadget if it came pre-set.


If your air conditioner constantly resetting at 85 degrees, you now know why and how to fix the issue. The information in this post should be enough for you to figure out the solution on your own. Fixing the thermostat yourself is a good first step before calling in the pros.


How can I keep the thermostat from changing the temperature in my home?

If you press “Hold,” your thermostat will keep its current setting until you change it. When you’re ready to get back to your regularly scheduled programing, just click the “Run” button. The programmable thermostat is a wonderful product of technological progress.

Why Your Thermostat Resets to 85 degrees:

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

  • The thermostat is now set at 85 degrees.
  • It’s time to swap out the batteries.
  • The thermostat’s fuse has been blown.

Why does my air conditioner suddenly change settings?

This is how they act on days when there is a high demand for electricity, as when temperatures soar and your air conditioner is working overtime. On that steamy day, when you’d like to keep your house at a comfortable 75 degrees, your energy company instead turns up the heat to 78 (or higher).

Why won’t my thermostat remember my setting?

The wiring is not secure. The thermostat may be dented, broken, or off-angle. You don’t have a sufficiently large heater or air conditioner for your home. There is a poor placement of the thermostat.

Why does my thermostat always have to reset itself?

Battery failure and acid leakage are common issues with this type of thermostat. Attempt a battery replacement to see if that corrects the reset issue. If your thermostat has a resetting feature and no common wire, you should get a new one.

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About the author


I am Ben , a seasoned HVAC specialist with over 6 of experience in the HVAC industry. I holds HVAC Certification and has a proven track record in providing expert advice on HVAC systems.