Honeywell Thermostat Keeps Going Up To 85 Degrees: SOLVED

Are you facing the frustrating dilemma of your Honeywell thermostat keeps going up to 85 degrees? This could be due to a thermostat’s low battery or power interruption that could also cause the Honeywell thermostat stubbornly stuck at 85 degrees.

There’s no need to endure sweltering or freezing conditions when your thermostat refuses to cooperate. 

A thermostat that won’t budge from 85 degrees can disrupt your comfort and energy efficiency, but fear not – solutions are within reach.

In this comprehensive guide, we’ll walk you through the steps to diagnose and resolve this common issue with Honeywell thermostats.

So, let’s roll up our sleeves and learn how to regain control over your Honeywell thermostat.

Understanding Thermostat Stuck at 85 Degrees

Before we embark on the journey of fixing your Honeywell thermostat stuck at 85 degrees, it’s essential to grasp the underlying causes behind this seemingly stubborn behavior. 

Several factors can contribute to this problem, and understanding them is the key to finding an effective solution.

Sensor Problems

One of the most common reasons for a thermostat reaching 85 degrees and staying there is a malfunctioning temperature sensor. 

This sensor is responsible for gauging the room temperature and instructing the thermostat on when to heat or cool. 

If it’s not functioning correctly, the thermostat may not respond appropriately to temperature changes.

Incorrect Settings

Sometimes, the issue might be as simple as incorrect thermostat settings. 

It’s possible that someone inadvertently adjusted the settings, causing the thermostat to maintain an undesired temperature.

Wiring Issues

Your thermostat relies on a network of wires to communicate with your heating and cooling systems. 

Loose, damaged, or improperly connected wires can disrupt this communication, leading to erratic temperature control.

Software Glitches (if applicable)

If your thermostat has smart features or programmable settings, software glitches or bugs could be the culprit. 

These issues can cause the thermostat to act unpredictably and maintain a constant temperature.

Preparatory Steps for Honeywell Thermostat Stuck at 85 Degrees Fixes

Before diving into troubleshooting and attempting to fix your Honeywell thermostat stuck at 85 degrees, it’s essential to be well-prepared. 

These preparatory steps will ensure you have everything you need and that you’re ready to tackle the issue effectively and safely.

Gather Necessary Tools and Materials:

   – Locate the user manual for your Honeywell thermostat. It contains valuable information about your specific model and troubleshooting steps.

   – Ensure you have common tools on hand, such as a screwdriver and a pair of pliers.

   – If you suspect wiring issues, consider having electrical tape and wire connectors available.

Safety First

   – Safety should be your top priority. Before starting any work, turn off power to your thermostat and HVAC system to avoid electrical accidents.

   – If you’re uncomfortable with electrical work or troubleshooting, consider seeking professional help.

Document Existing Settings

   – Take note of the current settings on your thermostat. Document the temperature settings, mode (heat, cool, or auto), and any programmed schedules.

   – This documentation will help you restore your preferred settings after resolving the issue.

Schedule a Convenient Time

   – Ensure you have enough time to diagnose and potentially fix the problem without rushing. Troubleshooting can sometimes be a time-consuming process.

Identify Your Thermostat Model

   – Knowing the specific model of your Honeywell thermostat is essential, as it allows you to access accurate troubleshooting instructions from the user manual or online resources.

Safety Gear

   – If you’re dealing with any electrical components, it’s a good idea to wear safety gloves and safety glasses to protect yourself from potential hazards.

Safety Preparation for Honeywell thermostat to reset to the default 85 degrees

When dealing with electrical devices like your Honeywell thermostat and HVAC system, prioritizing safety is paramount. 

Taking the appropriate precautions will protect you from potential hazards and ensure a smooth troubleshooting process. Here’s how to put safety first:

Turn Off Power

Before you start any work on your thermostat or HVAC system, shut off the power. Locate the circuit breaker or fuse that controls your HVAC system and turn it off. 

This step is crucial to prevent electrical shock or damage to your equipment.

Confirm Power Is Off

After turning off the power, use a non-contact voltage tester to verify that there is no electricity running to the thermostat or HVAC wiring. This extra precaution ensures your safety.

Wear Appropriate Safety Gear

If you’re working with wiring or electrical components, wear safety gloves and safety glasses to protect your hands and eyes from potential hazards.

Follow the User Manual

Refer to the user manual for your Honeywell thermostat. It often contains specific safety instructions and guidelines for working with the device.

Know Your Limits

If you’re not comfortable or experienced with electrical work, it’s advisable to seek professional help. 

Attempting advanced troubleshooting or repairs without the necessary expertise can be dangerous.

Keep the Work Area Clean and Organized

Maintain a tidy workspace to avoid tripping hazards or accidental damage to equipment. Organize your tools and materials for easy access.

Beware of Sharp Edges

Be cautious of sharp edges or corners on your thermostat or HVAC components. Accidental cuts or scrapes can happen during handling.

Stay Informed

If you’re unsure about any step of the troubleshooting process or encounter unexpected issues, consult a professional technician or the manufacturer’s customer support for guidance.

Troubleshooting Steps for Honeywell Thermostat Stuck at 85 Degrees

Now that you’ve taken the necessary safety precautions and prepared for the task ahead, it’s time to dive into troubleshooting your Honeywell thermostat that’s stuck at 85 degrees. 

We’ll walk you through a series of steps to diagnose and potentially fix the issue. Follow these carefully:

Step 1: Check Thermostat Settings

   – Begin by inspecting the thermostat’s display. Ensure it’s set to your desired temperature and mode (heat, cool, or auto).

   – Verify that the fan setting is appropriate (e.g., “Auto” or “On”).

   – If the settings seem correct, proceed to the next step.

Step 2: Test the Temperature Sensor

   – The thermostat relies on its temperature sensor to gauge the room’s temperature accurately. Check if there’s anything obstructing the sensor or if it’s dirty.

   – Use a soft brush or compressed air to clean the sensor gently.

   – Wait for a while and observe if the thermostat responds by adjusting the temperature. If not, proceed to the next step.

Step 3: Inspect Wiring Connections

   – Carefully remove the thermostat cover to access the wiring connections.

   – Examine the wires to ensure they are securely connected to their respective terminals.

   – Tighten any loose connections using a screwdriver.

   – If the wiring appears damaged or frayed, consider replacing it.

Step 4: Replace Batteries

   – If your Honeywell thermostat is battery-powered, replace the batteries. Low battery power can cause erratic behavior.

   – Follow the manufacturer’s instructions for battery replacement.

Step 5: Software Updates

   – If your thermostat has smart features or programmable settings, check for software updates.

   – Visit the manufacturer’s website or consult your user manual for guidance on updating the thermostat’s firmware.

Step 6: Power Cycle

   – As a last resort, perform a power cycle. Turn off the power to your HVAC system and thermostat, wait a few minutes, and then turn them back on.

   – This can sometimes resolve temporary glitches.

Step 7: Seek Professional Help

   – If none of the above steps resolve the issue, or if you’re uncomfortable with any part of the troubleshooting process, it’s advisable to contact a professional HVAC technician.

   – A professional can diagnose and address more complex problems and ensure your thermostat functions correctly.

Common Problems and Solutions of Honeywell Thermostat

In your quest to fix a Honeywell thermostat stuck at 85 degrees, it’s valuable to be aware of other common issues that may contribute to this problem. 

Below, we outline these issues along with their corresponding solutions to help you get your thermostat back to optimal performance:

1. Incorrect Wiring

  • Problem

Wiring errors or loose connections can disrupt communication between the thermostat and the HVAC system.

  • Solution

Double-check the wiring connections, ensuring they match the thermostat’s wiring diagram. Tighten any loose wires or replace damaged ones.

2. Temperature Calibration

  • Problem

Over time, a thermostat’s temperature sensor may become inaccurate, leading to improper temperature readings.

  • Solution

Recalibrate the thermostat by adjusting the temperature offset settings, following the instructions in your user manual.

3. Sensor Placement

  • Problem

The thermostat’s sensor may be poorly positioned or affected by nearby heat sources, leading to incorrect temperature readings.

  • Solution

Reposition the thermostat or sensor to a location away from direct sunlight, drafts, or heat-producing appliances. 

Ensure it’s in an area that represents the room’s average temperature.

4. Firmware Issues

  • Problem

Smart thermostats may experience occasional software glitches or compatibility issues.

  • Solution

Check for firmware updates through the manufacturer’s app or website. Updating the firmware can often resolve software-related problems.

5. Mechanical Failure

  • Problem

Over time, the thermostat’s internal components may wear out, leading to erratic behavior.

  • Solution

If your thermostat is older and none of the previous solutions work, it may be time to consider replacing it with a new model.

6. Battery Problems

  • Problem

Weak or depleted batteries can cause thermostat malfunctions.

  • Solution

Replace the batteries with fresh ones according to the manufacturer’s recommendations.

7. Inadequate HVAC System Maintenance

  • Problem

A poorly maintained HVAC system can affect the thermostat’s ability to control temperature accurately.

  • Solution

Schedule regular maintenance for your HVAC system, including cleaning filters, checking ductwork, and ensuring proper system functioning.

8. Compatibility Issues

  • Problem

If you recently upgraded your HVAC system or thermostat, compatibility issues may arise.

  • Solution

Confirm that your thermostat is compatible with your HVAC system. If not, consider installing a compatible thermostat or seeking professional assistance.

When to Call a Professional?

While many thermostat issues can be resolved through DIY troubleshooting and basic fixes, there are situations where it’s advisable to call in a professional HVAC technician. Here’s when it’s time to reach out to an expert:

Complex Wiring Problems

If you’re not confident in your ability to identify and fix wiring issues, it’s best to call a professional. Incorrect wiring can lead to more extensive problems.

Refrigerant Leaks

If your thermostat is part of a cooling system and you suspect a refrigerant leak, this is a job for a licensed technician. 

Handling refrigerants without proper training and equipment is dangerous and illegal.

Broken or Faulty Components

When components within your thermostat or HVAC system are damaged or malfunctioning, professional expertise is needed for diagnosis and replacement.

System Replacement

If your thermostat is outdated or incompatible with your HVAC system, a professional can help you select and install a new, compatible thermostat.

Smart Thermostat Configuration

Installing or configuring smart thermostats with advanced features may require professional assistance, especially if it involves connecting to your home’s Wi-Fi network or other smart devices.

Safety Concerns

If you encounter any safety concerns, such as unusual sounds, burning smells, or electrical issues, immediately turn off your HVAC system and contact a professional technician.

Energy Efficiency Improvements

Professionals can assess your HVAC system’s efficiency and recommend upgrades or adjustments to save energy and reduce utility bills.

Warranty Coverage

If your thermostat or HVAC system is under warranty, attempting DIY repairs could void the warranty. A professional technician can ensure repairs are covered.

System Sizing and Balancing

HVAC systems need to be appropriately sized and balanced to provide efficient heating and cooling. A professional can assess and adjust these factors.

Legal and Regulatory Compliance

Certain HVAC work may require compliance with local building codes and regulations. Professionals are familiar with these requirements.

Frequently Asked Questions (FAQs)

 What should I do if my thermostat has no power at all?

If your thermostat is unresponsive and has no power, check if the batteries need replacement (if applicable). If that doesn’t work, consult a professional to inspect and repair the wiring or thermostat itself.

How often should I replace the batteries in my thermostat?

Battery replacement frequency can vary based on the thermostat model and usage. Check your user manual for specific guidance, but a common recommendation is to replace batteries once a year or when the low battery indicator appears.

Can a dirty sensor really cause temperature issues?

Yes, a dirty or obstructed sensor can provide inaccurate temperature readings, leading to thermostat issues. Cleaning the sensor can often resolve this problem.

What if my thermostat is still under warranty?

If your thermostat is under warranty, it’s best to contact the manufacturer or an authorized service provider for assistance. DIY repairs may void the warranty.

Is it worth upgrading to a smart thermostat?

Smart thermostats offer advanced features and energy-saving capabilities. Consider upgrading if you want remote control, scheduling, and energy-efficiency features. However, ensure compatibility with your HVAC system.


Congratulations! You’ve taken the initiative to address the issue of your honeywell thermostat keeps going up to 85 degrees

Remember that resolving thermostat issues may require patience and persistence. If you’ve successfully resolved the problem, enjoy the comfort of a well-functioning thermostat. 

If not, don’t hesitate to contact a professional technician who can provide expert assistance.

By following the guidelines in this guide, you’ve taken a proactive step toward regaining control of your home’s temperature and energy efficiency. 

We hope your journey to a perfectly functioning thermostat has been a successful one. Stay comfortable!

Scott Maupin