Carrier Air Conditioner Troubleshooting Manual (7 Quick Fixes!)

A simple-to-follow Carrier Air Conditioner Troubleshooting Manual is the key to fixing most issues affecting the air conditioner. In most cases, you don’t need an expert to identify faults and troubleshoot them, just the manual.

You can use a manual to troubleshoot your Carrier air conditioner when it doesn’t start, turn off, cool, work after a power outage, or respond to the remote. Additionally, you can troubleshoot a blinking operation light or a non-running compressor.

Those are the seven issues that this troubleshooting manual shall focus on. We’ll look at the likely reasons behind the seven AC issues and what to do in each case to troubleshoot them.

In the end, you’ll also learn how to prevent some of these issues from recurring. So, let’s jump into it!

Carrier air conditioner troubleshooting manual

In a hurry? Find below a quick troubleshooting manual for the various Carrier air conditioner issues:

Quick Carrier Air Conditioner Troubleshooting Manual

ProblemLikely CauseQuick Fix

Carrier Air Conditioner Not Starting

The AC isn’t connected to power, failed power supply, electrical fault, non-running compressor, or aged AC

Ensure the AC is connected to the power, reset the breaker if it’s OFF, and replace the fuse if it’s faulty. Call an HVAC technician to handle the other checks and replace the AC if older than ten years.

Carrier Air Conditioner Won’t Turn Off

Filthy condenser coils, shorted thermostat, or failed component (thermistor, temperature control board, relay board, or main control board)
Clean the condenser coils if they are dirty and replace the thermostat, thermistor, temperature control board, relay board, or main control board if faulty. 

Carrier Air Conditioner Not Cooling

Undersized unit, wrong temperature mode, blocked indoor or outdoor unit, dirty air filter, low refrigerant, frozen evaporator coils, or failed component (compressor, thermostat, fan, thermistor, run capacitor, heat pump, or main control board)Get a bigger Ac if it’s undersized, set it on ‘cool’ or ‘auto’ mode, and remove anything obstructing the indoor or outdoor unit. Clean a dirty air filter and call an HVAC expert to handle the rest


Carrier Air Conditioner Not Working after Power FailureTripped breaker or a malfunctioning thermostat

Reset the thermostat and the AC breaker


Carrier Air Conditioner Won’t Respond to the Remote

Wrongly set or dead remote batteries, blocked or long signal range, or bad remote control or AC control board

Ensure the batteries are correctly positioned and replace them if you’ve been using them for a year. Use the remote at a close distance, away from obstructions, and replace it (the remote) or the AC’s main control board if faulty

Blinking Operation Light
Dirty air filter, frozen coils, low refrigerant, wrong installation, failed compressor, or an electrical faultClean the air filter and if the blinking doesn’t stop, call an HVAC technician

The Compressor Won’t Run

Failed power supply or the defective component (temperature control board, overload, relay board, thermistor, capacitor, or main control board) or compressorEnsure the AC has power and if you cannot fix it, call an HVAC technician

7 Common Carrier Air Conditioner Problems for Troubleshooting with a Manual

Shared below are the most typical Carrier air conditioner issues and the relevant basic troubleshooting practices

1. Carrier Air Conditioner Not Turning On (Won’t Start)

Your Carrier air conditioner won’t start for different reasons, and the most probable ones are:

  • The AC might not be connected to power – The air conditioner might not be plugged into the power socket, and if it is, it might not be turned on. Any of the two issues will prevent it from turning on.
  • Failed power supply – Two issues could disrupt your air conditioner’s power supply; tripped breaker (flipped off) or a blown-up fuse (won’t show electrical continuity on a multimeter). So, check both.
  • Electrical fault – If there is a wiring fault, which an expert can help you check, the air conditioner won’t get enough power to start.
  • Non-running compressor – The air conditioner won’t start if the compressor doesn’t run. An expert, again, can help you check the compressor.
  • Aged unit – Air conditioners fail when they run for ten years or more. Thus, consider your AC’s age.


Ensure the AC is well-plugged into the electrical outlet and switched on. Check the electrical box to rest the breaker if it’s off and if the fuse lacks electrical continuity, replace it.

If the AC still doesn’t start, call an HVAC pro to check for any electrical fault or a failing compressor. But if the unit is older than ten years, replace it. However, getting a technician’s assessment before purchasing a new AC is essential.

2. Carrier Air Conditioner Not Turning Off

Sometimes your Carrier AC may start but run nonstop. If so, here are some issues that could be preventing it from turning off:

  • Filthy condenser coils – Dirty condenser coils fail to dissipate heat and overwork the compressor. Once the compressor overworks, it runs nonstop.
  • Shorted thermostat – If the thermostat short-circuits, it fails to stop the compressor from running, causing the AC not to go off.
  • Failed component – The air conditioner may also run nonstop if the thermistor, temperature control board, relay board, or main control board is faulty. Other than the thermistor, these components will fail to supply power to the compressor, preventing the Ac from turning off.


Clean the condenser coils if they are filthy, and replace the thermostat if it won’t show electrical continuity on a multimeter. If the Ac still doesn’t turn off, call an HVAC technician to inspect the mentioned components for fault and replace them.

Carrier air conditioner operation light blinking

3. Carrier Air Conditioner Not Blowing Cold Air But Running (Won’t Cool)

Cooling is arguably an air conditioner’s most essential function. So, a Carrier air conditioner that won’t cool despite running should be a considerable concern, and here are the most likely explanations for that:   

  • Undersized unit – Your Carrier air conditioner won’t cool; if it does, it won’t be uniform cooling if it’s small. Its capacity (BTU) or output (kW) should match the room size.
  • Wrong temperature mode – For cooling to occur, you should set the AC’s thermostat on either ‘cool mode’ or auto. Any other mode will stop it from blowing cold.
  • Blocked indoor unit – If things are curtains, furniture, kids’ toys, and other household supplies are blocking the indoor unit; the AC won’t blow cold air properly.
  • Blocked outdoor unit – The condensing unit outside, which features the condenser coils, compressor, and run capacitor, should be dirt-clogged. If it is, then the AC won’t blow cold air properly.
  • Dirty air filter – A clogged air filter restricts the proper flow of air, inhibiting its adequate cooling. It can not only stop the air conditioner from cooling, but it may also turn itself on.
  • Low refrigerant – If the refrigerant leaks and its level drops, it cannot absorb the hot indoor air, so the air conditioner fails to cool.
  • Frozen evaporator coils – The evaporator coils also stop the air conditioner from cooling when they ice over. That’s likely due to a clogged air filter or inadequate refrigerant.
  • Failed component –Lastly, the AC will fail to blow cold if the compressor, thermostat, fan, thermistor, run capacitor, heat pump, or main control board fails. An expert can help you inspect these components for faults.


Consider the table below to identify if your Carrier air conditioner is undersized. If it is, then get an option with more considerable energy output.

Room Size (square meters)Room ExampleAC Output (in kW)
9-12Study room or home office2.10kW
9-17Kids’ room or guest room2.36kW
15-25Master ensuite3.55kW
25-35Standard living space or theatre room5.05kW
35-48Large dining7.00kW
48-60Large living space8.00kW
50-72Open-plan living space9.10kW

If the air conditioner is the right size, check its thermostat setting and ensure it’s either on cool mode or auto. If it’s not, set it correctly. Then remove any blockages around the indoor and outdoor units. And if the air filter is dirty, clean it.

Call an HVAC pro, however, for the other issues. That includes checking the refrigerant for leakage, evaporator coils for icing over, and the components for failure.

4. Carrier Air Conditioner Not Working After Power Outage

Sometimes the air conditioner won’t run after a power loss or failure. That’s likely to happen due to a tripped breaker or malfunctioning thermostat. So, it’s essential that you check the two and reset them.


As mentioned, you ought to inspect the breaker and thermostat and reset them after a power outage. Here’s how to go about it:

  • Turn off the thermostat
  • Flip the breaker off (if it’s on), then ON
  • Wait for 30 minutes to switch on the thermostat
  • Set the thermostat on Cool mode
  • Then wait for the AC to turn on and run

5. Carrier Air Conditioner Not Responding to Remote Control

If the air conditioner won’t respond to the remote control, the problem is either with the remote (which is most likely) or the air conditioning unit. In that case, here are the things to check:

  • Wrongly set batteries – If the batteries are put incorrectly (incorrect polarity), the remote control won’t work. So, check them.
  • Dead batteries – The remote control batteries need replacing after one year of use. If they are older than that, the remote control won’t work.
  • Blocked signal or long-range – If something like a wall is blocking the remote control’s signal or you are holding the remote at a distance, the remote won’t work.
  • Bad remote control – The remote control itself could be defective. Its LED could be broken, causing it not to work.
  • Defective AC control board – Lastly, if the issue is not with the remote, it’s highly likely with the air conditioner’s main control board. The AC won’t respond to the remote if the control board is defective.


Set the remote batteries correctly if their polarity is wrong but if they are older than one year, replace them. Meanwhile, ensure you operate the remote at a close distance (10 feet radius) and way from barricades.

If the AC is still non-responsive, try to operate it without the remote. If it works, the remote is likely faulty, and you should replace it.

But if nothing is wrong with the remote, consider replacing the main control board or getting a new Carrier AC.

Carrier air conditioner not turning on

6. Carrier Air Conditioner Operation Light Blinking

Whenever the status or operation light starts to blink, it’s usually a sign that something is wrong. The issue in such a case could be any of these:

  • Dirty air filter – This is the most likely reason behind the blinking operation light. Thus, it should be the first thing to check.
  • Frozen coils – The Ac will also flash the operation light if the evaporator coils freeze.
  • Low refrigerant – One way to identify a drop in the refrigerant level is by recognizing a flashing status light.
  • The wrong installation – If the AC was wrongly installed, it might blink the operation light.
  • Failed compressor – A malfunctioning compressor sometimes indicates by blinking the operation light.
  • Electrical fault – If there’s a wiring issue, the air conditioner may start blinking.


Start by checking the air filter. Clean it if it’s filthy and if the blinking won’t stop or repeats shortly after, call an HVAC expert to handle the other issues.

7. Carrier Ac Compressor Not Turning On

Lastly, you wouldn’t want the compressor to fail. If it does, the air conditioner may fail to run, and if it does, it won’t cool properly. Issues that could prevent the compressor from turning on include the following:

  • Failed power supply – Without power, the compressor won’t run. So, check for an issue like power loss, a tripped breaker, an unplugged cable, or a defective socket.
  • Defective component – The compressor will also not turn on if the temperature control board, overload, relay board, thermistor, capacitor, or main control board is faulty. An expert can help you determine which of them is defective.
  • Dead compressor – If the issue is not with the components, it’s most likely with the compressor. The compressor could be dead and need a replacement.


Ensure the air conditioner has power. It should be ON. If it’s not and you cannot diagnose the issue, call a technician. Also, call an HVAC technician to check the components and the compressor for faults. If any of them is defective, replace them.

Closing Thought:

The above Carrier Air Conditioner Troubleshooting Manual is handy when dealing with various issues affecting your Carrier AC. So, use it before approaching a technician and save time and cash. You may never know; the AC issue could be something you could troubleshoot yourself.

Leave a Comment