Rheem Air Conditioner Not Cooling (12 Issues Fixed!)

Is your brand new Rheem air conditioner not cooling, and you can’t explain it? Perhaps it’s an old one that has been working fine but won’t blow cold air now. If so, you can fix it, but you must find out why.

Your Rheem air conditioner won’t cool because of a wrong cooling capacity or thermostat setting, a non-working thermostat, filthy filter, clogged condenser coils, leaky door, frozen evaporator coils, blocked or leaky ductwork, non-working compressor, refrigerant leak or bad control board..

So, there are a dozen possible explanations for why your Rheem air conditioner won’t blow cold air. But with every problem comes an appropriate solution, and this troubleshooting guide will help you get your Rheem AC back cooling.

After looking at why the AC won’t cool, we’ll look at some relatable issues and questions that will solve other problems affecting your AC. Let’s dive in!

In a hurry? Consider the 12 reasons below and their fixes to troubleshoot your non-cooling Rheem air conditioner.

Rheem Air Conditioner Not Blowing Cold Air – Quick Troubleshooting Guide

Why Is My Rheem Air Conditioner Not Cooling?

Generally, your Rheem air conditioner is not blowing cold air due to one of the 12 reasons shared below:

1. Wrong Cooling Capacity

Your Rheem air conditioner should be the correct size. Its capacity, expressed in British Thermal Units (BTU) or tons, should match your space square footage. The air conditioner won’t cool the space if that’s not the case.

You might even fail to notice the air conditioner running, especially if it’s undersized. And if it’s oversized, it’ll turn on and off repetitively.

Fix

Ensure you match your space with the correct Rheem air conditioner capacity. If your existing air conditioner doesn’t have the cooling capacity to fit your space, replace it.

That brings us to the table below:

Note: 1 ton = 12,000 BTU/Hour

2. Wrong Thermostat Setting

When set on Cool or Auto mode, your Rheem air conditioner only blows cold air. It won’t, however, when it’s running on heat or fan mode. For that reason, it’s essential to check the thermostat setting first.

While at it, ensure the thermostat reads a lower value than your room temperature. If the value is higher, the air conditioner will blow hot – instead of cold.

Fix

Set your air conditioner on either Cool Mode or Auto. Also, ensure the thermostat reads a lower value (by a few degrees) than the room temperature.

3. Non-Working Thermostat

The thermostat’s job is to monitor your room’s temperature, enabling the compressor to run and allowing the AC to blow cold air. If it is not working, the AC won’t cool.

Sometimes, the problem could be dead thermostat batteries, but if the batteries are not energy-drained, the thermostat itself could be defective.

Fix

Replace the thermostat and see if you can adjust the AC’s temperature. If it’s impossible, put the thermostat on ‘Cool Mode’ and check if it has continuity using a multimeter. The lack of continuity means the thermostat is defective, and in such a case, replace it.

4. Filthy Filter

The air filter should be replaced every 2-3 months. If you don’t, it will accumulate a lot of clogs, which will interfere with its performance. In such a case, the blocked air filter will restrict airflow. (apkshelf.com)

Fix

Replace the air filter if it has been over two months. While at it, make it a habit of replacing the filter every 2 -3 months to avoid such an issue.

5. Clogged Condenser Coils

The outdoor unit is exposed to dust and dirt, among other filths. Over time, the condenser coil clogs up, and when it does, it’s unable to dissipate heat. That means your air conditioner cannot blow cold air inside the house.

Fix

Inspect the condenser coils outside for dirt clogging and clean them. If possible, use a condenser cleaning brush and also clean the other parts of the outdoor unit.

6. Leaky Doors

Is your door open? Sometimes opening the door too long interferes with the air conditioner’s cooling performance. The door could allow hot air from outside while encouraging more cold air to escape. In the end, it feels like your air conditioner is not working.  

Don’t forget about the windows too. If there are open spaces around them, they could also encourage cold air to escape. So, while it’s okay to open the door, you shouldn’t do it too long.

Fix

Shut the door, especially if it has been open for too long. Meanwhile, look for any spaces, perhaps on the wall or around the doors and windows, and seal them. You can use sealant to proof your house against air leakage.

7. Frozen Evaporator Coils

The evaporator coils in the inside unit could also be why your Rheem air conditioner won’t blow cold. If there is a refrigerant leakage, for example, these coils will freeze over, and once that’s the case, the air conditioner cannot cool.

Fix

Call an HVAC pro if the condenser coils look frozen. They’ll help you fix it.

8. Blocked or Leaky Ductwork

If the ductwork is clogged, it’ll restrict airflow. That means your Rheem air conditioner won’t cool. And if the ductwork is leaky, it will encourage the cold air to escape.

Fix

Inspect your ductwork and clean it if it’s blocked. If it’s leaky, use sealant to seal the open spaces.

9. Rheem Air Conditioner Compressor Not Working

The compressor is a critical part of your air conditioner’s operation. If it’s not working, your air conditioner won’t run.

Consequently, it won’t pump the coolant/refrigerant across the condenser. In the end, that stops the air conditioner from blowing cold air.

Sometimes the compressor won’t run because it’s not powered, but in some cases, it won’t because it’s defective. So, you’ve to determine what the issue is.

Fix

Check if the compressor outside is powered and power it on if that’s not the case. However, if you can’t hear the compressor running, have an expert check it and replace it if it’s defective.

10. Refrigerant Leak

If the refrigerant level drops, your Rheem air conditioner will not cool your space. That could happen due to physical damage to the unit or a wrong installation.

Overall, a refrigerant leakage is not easy to diagnose, and so this is an area an HVAC expert can help you with.

Fix

Call an HVAC expert to help you identify the source of the refrigerant leakage and fix it.

11. Bad Control Board

The control board’s job is to regulate the air conditioner’s power supply, especially to the compressor and motor. Over time, the control board wears out, and in case of a power surge, the control board may short-circuit, thus unable to do its job.

Once that happens, your Rheem air conditioner cannot run or blow cold air.

Fix

Consider replacing the control board if it shows signs of burning and the air conditioner doesn’t turn on. An expert technician can help you inspect the board for faults to avoid a misdiagnosis.

12. Aged Unit

Lastly, your Rheem air conditioner might not be cooling because it’s too old to run correctly. Ideally, air conditioners have a lifespan of 10-12 years, but with good maintenance, they can go for 15 years or slightly more.

So, is your air conditioner older than 12? Then that could be the problem.

Fix

Consider replacing your Rheem air conditioner if it’s older than 12 years.

Rheem Air Conditioner Running But Not Cooling

While you expect your Rheem air conditioner to blow cold once it starts to run, sometimes it won’t. Here are some issues that could stop a running Rheem air conditioner from cooling:

• A wrong thermostat setting, especially the wrong mode
• Clogged air filter
• Frozen evaporator coils
• Leaky ductwork
• Low refrigerant

Rheem Air Conditioner Not Turning On

There are several reasons why a  Rheem air conditioner won’t turn on. They include the following:

• Power outage
• Failing to turn on the air conditioner
• Faulty power outlet
• Dirty condenser coils or air filter
• Refrigerant leakage
• Wrong thermostat setting

People Also Ask

1. Why Is My Rheem Air Conditioner Not Working?

Your Rheem air conditioner is not working because it’s too old to run (over 12 years) or undersize (the wrong capacity). If that’s not it, it could be the lack of power or a malfunctioning thermostat.

2. Why Is My Ac Coming On But Not Cooling?

Your Ac is coming on but not cooling because of a wrong thermostat setting or a clogged filter. The thermostat should be on Cool/Auto mode, and the filter should be clean. Or, it could be due to frozen coils, refrigerant leakage, leaky ductwork, or the wrong size.

3. Is Rheem Air Conditioner Good?

Rheem air conditioners are known for their energy efficiency and powerful cooling capacities. These units are also strongly built and reliable in performance – not forgetting their modern and easy-to-use designs. So, yes, Rheem’s air conditioners are good.

4. Where Is the Reset Button On a Rheem Air Conditioner?

The Rheem air conditioning reset button is adjacent to the copper lines, which you’ll find towards the bottom of the AC’s rubber case. But if you can’t find it, check its position in your air conditioner manual.

5. How Should I Reset a Rheem Air Conditioner?

You can reset your Rheem air conditioner using its reset button. But first, turn off the air conditioner by flipping the circuit breaker off. Then press the reset button and wait a few minutes before restoring power.

Concluding Thoughts On Your Rheem Air Conditioner Not Cooling:

Shared are the reasons a Rheem air conditioner won’t cool. Remember, it could be the wrong unit size or thermostat setting, a failing thermostat, a filthy air filter or condenser coils, or frozen evaporator coils.

Don’t forget to check for blocked or leaky ductwork, refrigerant leakage, a short-circuited control board, and a non-kicking compressor. And if the air conditioner is older than 12 years, replace it as it’s too old to cool optimally.

Also Read:

• Why Your Rheem AC Fan Won’t Work