Carrier Air Conditioner Error Code 72 [Reasons & Fixes]

You bought a carrier air conditioner recently and it started showing error codes. It’s quite normal that you will be worried about it. You looked in the manual but couldn’t find anything in that, right? 

So, you’re asking why the carrier air conditioner error code 72 shows up?

The high-stage thermal cut-out causes Carrier air conditioner trouble code 72 to appear. You may also encounter it if the thermostat is incorrectly configured. Some folks see this error code as a result of a filthy air purifier. The level of refrigerant might also be a factor.

Well, this barely summarizes the depth of this error code. We have detailed information about this problem below.

Let’s jump into the article. 

Why Does Carrier Air Conditioner Error Code 72 Show Up?

There are 6 reasons why error code 72 appears in a carrier air conditioner model. Check out each of these cases below-

Case 1: Thermal Cut-out

A high-stage thermal cut-out might be one of the key causes of error code 72. While there is considerable stage demand, the compressor action is identified and then disappears. 

The cause is an internal compressor overload trip/start relay. As well as a capacitor that has been left in the circuit for too long. In that case, Carrier Bryant Payne capacitor replacement can come in handy. You can find it on amazon.

If your high-stage thermal cut-out occurs more than once, you may get error code 72 as well. In that situation, you must identify the internal issue so that it does not occur again.

Case 2: Dirty Air Purifier 

A jammed filter and obstructed airflow might result from a lack of service. In these cases, they can result in decreased efficiency. Or, in more severe circumstances,  system collapse.

Next question is, how to detect a dirty air purifier? Well, a dirty filter may cause the following symptoms-

• Your house’s air temperature is higher than usual.
• Your cooling controls appear to have less airflow than usual.
• The air conditioner operates for a short time before turning off and restarting.

Checking for a filthy air filter seems to be the most common step in AC maintenance. Your air conditioner is more than just the outside unit on the side of your house.

Error code 72 can be due to this damaged air purifier. In that case, yes, it’s in your unit’s best interest to replace the air purifier. In this situation, Filter-Monster Replacement Air Purifier Cartridge is a good option. It fits carrier ac units perfectly. You can get it from amazon.

Case 3: Refrigerant Level is Low

To keep your home cold, the air conditioning system makes use of a substance known as refrigerant. The cooling system is required for relaxation during the day, and greater effectiveness at work or at night. Without it, your ac may work at day but night.

In a constant loop, the refrigerant is circulated via copper pipes. The interior evaporator coil and the outside condensation device. 

The refrigerant removes heat from your home and transfers it outside. While it runs past your AC system, the inside air is cooler, less moist, and more pleasant.

If your refrigerant levels drop, you may encounter the following air conditioner issues–

• The house is not staying cold enough.
• operating constantly or for longer periods of time than usual.
• Several times in succession, the air conditioner turns on, and then rapidly turns off.

Case 4: Issues with the Electrical Panel

You may have lost power to the grid when there’s no air flowing from the vents. The home is excessively heated, and the system isn’t working at all. Because your air conditioner is electrically powered, find your home’s panelboard (breaker box). 

Look for a blown transformer or a tripped circuit breaker that’s not in the ON position. Please remember that your outside air conditioner will be linked to a separate one. The 220 or 240-volt disconnection or fuse box is placed near the air conditioner unit. 

At the switchboard, the air conditioner is also attached to a power switch or fuse. It can also make noise from the power outage box. 

Case 5: Frozen Evaporator Coil 

The evaporator coil in a split-system centralized air conditioner is usually installed inside the residence. Alternatively, it can be in the basement as part of the air processor unit. 

The evaporator coil is normally situated within the fan coil cupboard if it’s a fan coil. You may have a clogged evaporator coil if you notice any of the following symptoms-

• Increased utility bills
• Insufficient cooling
• Excessive condensate leakage in the vicinity of your indoor unit
• Frost or ice accumulating on your evaporator coil cabinet’s copper refrigerant lines
• Frost growing on outside refrigerant pipe or the outdoor unit

In that case, you might see the error code 72 for a clogged evaporator coil. You should call a mechanic if you wanna unclog the coil.

Case 6: Defective or Broken Condensing Unit 

The condensation unit is required in the closed cycle system for vaporizing the air conditioner. In a conventional split-system central air conditioner, the condensation unit is located outside. It also comprises the outside coil, the turbine, the condensation fan, and its electrical controls. 

When you discover the following symptoms of a malfunctioning or damaged condensing unit, it’s time to repair it.

• No or insufficient cooling
• The system is rapidly going on and off. 
• System operating indefinitely or for abnormally extended periods of time.
• Frost or frost on the copper refrigerant tube or coil
• The condensing unit does not turn on at all.

Carrier Air Conditioner Error Code 72: What To Do?

When you discover the problem code, you have three options-

Fix 1: Restart the Process

Restart the process to ensure that the error message is not an error. Only do this if you are familiar with your home’s electrical devices. This procedure will remove the air conditioner’s onboard memory and restart it. 

Climate, lightning storms, blackouts and brownouts, and power oscillations can all create problems. These might be the causes of your air conditioner turning down for safety. However, it is not always successful. It is worth a try before paying for a service request. 

Fix 2: Disconnect the Power Source 

Disconnect your air conditioning system from its power source. And switch off the isolation adjacent to the outside unit. Or they will cut off the electricity to your house from the main board.

Allow for 15–30 minutes. The onboard memory will be erased during this period. Restart your device by turning the electricity back on. If the problem requires professional assistance, the error code will recur.

Tip 3: Call An HVAC Professional 

Sometimes, it is quite normal to know that you won’t understand the process of solving the problem. 

Carrier has a number of customer support systems for such situations. Call them to help you out before this minor problem escalates into a large problem. 

Frequently Asked Questions (FAQs) 

What is the reason for a high-stage thermal cutout?

The compressor’s internal overload is the main reason for a high-stage thermal cutout. It might be overheating, failing to start, or stopping. There is nothing you can do as a householder to repair it yourself.

How long will Carrier Infinity be available?

Carrier Infinity will be available for almost 10 years. Because of Carrier’s unrivaled dependability, your system will most likely survive considerably longer. Please contact the electrician if you are considering a cutting edge. Carrier Infinity system or any of our other products.

When should I replace my air conditioning thermostat?

YOu should replace your air conditioning thermostat after 10 years. The majority of thermostats have a 10-year lifespan. After 10 years, they may begin to exhibit symptoms of age and wear. It will indicate that it is time to replace them. 

Bottom Line 

I think I talked about all the things about carrier air conditioner error code 72. You should first identify the problem behind the error. Then you should seek a solution.

You may attempt it on your own. In that case, you will save money and do it whenever you want. But if you feel it’s complicated, then you can always call for expert help. 

Have a safe life. Best of luck.

Tim David

HVAC tech with over 30 years of experience. Retired and doing repair work on the side around Madison County, AL.