AC Not Responding to Thermostat? Here’s What Could Be Wrong

Even the simplest thermostat has an important job — regulating the temperature in your house. A thermostat works by sensing the ambient temperature in a space, then turning your air conditioner on or off to maintain the temperature you’ve set for the room.

Smart thermostats are ideal for Indiana’s hot, humid summers and cold, snowy winters. A smart thermostat optimizes energy use and monitors both indoor and outdoor temperatures, making automatic adjustments as needed. They also come with features such as:

• Machine learning
• Voice control and remote control features
• WiFi options
• Data and energy tracking
• And more

Depending on the type of cooling system you have, the AC may also have several cooling levels, making it easier for the system to maintain your preferred indoor temperature. 

If your AC isn’t responding to the thermostat, the best solution is to contact an HVAC expert to find the root cause of the issue. At Dugan Air Heating & Cooling, our local techs are experts at thermostat repair and replacement, delivering top-quality AC services and a first-class customer experience to our service area.

Common Causes of Thermostat-to-AC Communication Issues

Some of the most common reasons why your thermostat’s not turning on the AC include the following.

Improper installation 

Thermostats must be installed correctly to function. If your thermostat isn’t installed properly or has been placed too close to windows, doors, or heat sources like a fireplace or stovetop, it won’t be able to accurately read the room’s temperature, causing ongoing temperature issues. Contact the professionals at Dugan for reliable thermostat installation.

Faulty thermostat sensor 

If the sensor in your thermostat isn’t reading the room temperature correctly, it won’t turn the air conditioner on when needed. A faulty sensor can be repaired or replaced by an HVAC expert. 

It’s in recovery mode

Recovery mode means your AC is working to return to the programmed temperature you’ve set it to after being turned off, or it’s in an energy-saving state. For example, if you program the thermostat to turn the AC down at night, it’ll move into recovery mode as it turns back on in the morning. 

The system needs maintenance

Several maintenance issues could cause problems with communication between the thermostat and your air conditioner, or make it more difficult for the air conditioner to hit your desired temperature promptly. A dirty thermostat, filters, coils, or condenser unit may cause the system to struggle to meet your needs.

Low refrigerant levels, mechanical problems, and other issues can also affect your system’s cooling capacity. Regular tune-ups help prevent these types of issues.

There’s an electrical issue

Loose or corroded wires often happen over time due to general wear and tear. This disrupts the electrical connection, preventing the system from receiving instructions from the thermostat. Your electrical system is complex, and it can be dangerous to perform electrical work on your own. If there’s an electrical problem with your thermostat, count on Dugan for assistance.

Quick Thermostat Troubleshooting Steps You Can Try

Not every thermostat problem needs professional repair. Before calling Dugan, try these simple troubleshooting steps to see if you can resolve the issue yourself. 

Check the batteries

Thermostats are typically wired into your electrical system, but most units also use batteries to power the digital displays and operate the system. Dead or dying batteries in your thermostat can cause various disruptions, including preventing it from communicating with your air conditioner.

Luckily, swapping out the batteries is an easy DIY fix: 

• Step 1: Turn the thermostat off.
• Step 2: Slide or gently pull the housing off the wall-mounted section. 
• Step 3: Check the back of the thermostat to determine the type of battery required.
• Step 4: Replace the batteries, ensuring the positive and negative terminals are correctly aligned.
• Step 5: Replace the cover and test the system.

Check the thermostat settings

The simplest solution to determine if your thermostat is on but the AC is not running is to check whether the settings are correct. Make sure the thermostat is set to “cool” and that the preferred temperature hasn’t been adjusted. 

You can also try resetting the thermostat. Like other electrical systems, sometimes a hard reset is all it needs to get working correctly again. 

Clean inside the thermostat 

Dirt, lint, and hair may be causing connection problems inside your thermostat. If you have a standard mechanical or electromechanical thermostat, you can gently clean it using a soft brush or some compressed air. When cleaning out the thermostat, you’ll need to slide or pop the cover off. Be gentle when cleaning, and avoid touching contact points, loose or corroded wiring, or other electrical parts. 

If you have a smart thermostat, don’t take it apart or open it up. These devices aren’t built to open, so they only need a light dusting on the outside to keep them clean.

Check the fuse box

A tripped circuit breaker could be a reason power isn’t reaching your thermostat, your air conditioner, or both. Check your electrical panel to see if a breaker has tripped. If you reset it and it trips again immediately, there’s probably an ongoing electrical problem that needs to be fixed. Turn the system off and contact an expert. 

When To Call an HVAC Professional

Sometimes, if the thermostat says it’s cooling but the AC’s not on, you’ll need professional help. A faulty AC can prevent the system from turning on, and it can also prevent the thermostat from communicating with the system properly. Some signs you need professional cooling system repairs include: 

• The system is turning on and off frequently (short cycling) without fully cooling the room.
• Hissing, grinding, squealing, or other sounds are coming from the AC. 
• The thermostat or the AC is having electrical problems. 
• Bad smells are coming from the AC or the vents. 
• The thermostat or the air conditioning unit won’t turn on at all. 
• Your energy bills are rising. 

At Dugan Air, our team understands the frustration of a failing or broken air conditioning system, especially when the weather is hot. Count on us to be there for you with personalized, honest assistance, including financing options, 24/7 emergency assistance, and help finding rebates and tax incentives for energy-efficient appliances and system installations in your home.

Contact Dugan Air for Expert HVAC Service and Thermostat Repair

If you need professional thermostat repair, Dugan Air Heating & Cooling is available now.  Our service area includes Johnson, Nashville-Brown, and Morgan Counties. Call us or schedule service online through our easy-to-use form, and we’ll respond promptly with the premium service we’re known for. Contact us today to experience the Dugan Difference!