Rheem Air Conditioner – Troubleshooting Guide

The majority of Rheem air conditioners are affordable and, on average, get high customer ratings, so no wonder a lot of homeowners choose to go for a cooling unit manufactured by this company. However, that does not mean that you wouldn’t have to troubleshoot the AC, at one point.

When your Rheem air conditioner isn’t cooling change the air filter and clean the condenser coils; a defective thermostat or a failed control board might also be to blame. In case the fan isn’t working, check the fan motor, motor bearings, and the capacitor – these parts might require replacement. 

Today, we are going to mention the most common reasons why a Rheem air conditioner may not be working the way it should be and what you can do about these issues.

Top Reasons Why Your Rheem Air Conditioner Isn’t Cooling

A Clogged Air Filter

What it is: the main job of the air filter is to catch various pollutants and particulates, such as pet dander, dust, and mold, for example.

These filters prevent the AC from getting contaminated with debris and, at the same time, catch a lot of particulates that could otherwise be circulating around the house.

How it fails: the filter needs to be changed every few months or so. The more dirt gets accumulated in the filter, the less air it would be able to let through the unit.

This also reduces the cooling capacity of the system.

How to fix: you should try cleaning the filter or replacing it with a new one.

Dirty Condenser Coils

What it is: the system’s refrigerant passes through the coils. This is where the heat dissipates.

How it fails: the more the unit works, the more air gets circulated through the system. As a result, dust and dirt will start to build up on some parts of the unit.

Dirty condenser coils are not able to dissipate the heat, which means that the air conditioner will fail to cool your house.

Have a Question? Ask HVAC Technician

Click here to use the chatbox to speak with one of our technicians.
No in-home service calls. No appointments.

How to fix: simply check the coils and clean them, if they are dirty.

A Defective Thermostat

What it is: a thermostat is a device that controls the temperature in your house. It uses a sensor to determine whether or not the temperature in the building is right.

If it’s too hot or too cold, the thermostat will send a signal to the heating or cooling unit.

How it fails: the thermostat might stop working properly because of its age, a defect, sludge, or overheating.

How to fix: to check, if the device is still functioning, set your AC to cooling and use a multimeter to find out, if the thermostat has continuity.

In case the multimeter didn’t show anything, replace the thermostat.

A Failed Control Board

What it is: this part of the system regulates the voltage to the fan motor and the compressor. 

How it fails: the vibrations in the AC might cause the wiring to shake loose over the years. Moreover, the transistors in the control board can easily get damaged by static electricity, power surges, and age.

How to fix: you might have to replace the control board, but better leave this part to a professional HVAC technician. 

Reasons the Fan Isn’t Working

Worn Out Motor Bearings

What it is: motor bearings are the things that allow some parts of the motor to rotate freely (without causing friction). Usually, there are 2 bearings on the front of the motor.

How it fails: the majority of the motor compartments in air conditioners have sealed bearings, which helps avoid getting this part of the system contaminated.

If you have had your unit for quite a few years already, then the motor bearing might have gotten worn out over the course of time.

How to fix: you can try to turn the blade by hand. If you are not able to do that freely, then the motor bearings (and the motor) need to be replaced.

If you can easily turn the blade, then it looks like your fan motor is simply not getting any power.

A Defective Dual Shaft Fan Motor

What it is: such a motor has two blades – one of them draws the air over the condensing coil and the other one directs the air right over the evaporator coil.

How it fails: just like in our previous example, the bearings of the fan motor could have become looser over time. They can also bind.

How to fix: try wiggling the motor shaft. If the thing won’t turn at all or is loose – replace the dual shaft fan motor.

A Problem with the Main Control Board

What it is: the main control board is the part of the system that provides voltage to the whole unit. If this thing is defective, it won’t be able to make the fan work.

How it fails: the control board can get worn out throughout the years. It can also fail because of power surges and static electricity.

Hint: static electricity might become a problem if your house has low humidity levels.

How to fix: unfortunately, you might have to replace the main control board.

A Burned-Out Capacitor

What it is: basically, a capacitor is an electronic component located inside the air conditioner that is temporary storage for electricity. The motors, for example, are all powered by the capacitor.

How it fails: age-related wear and tear, improper voltage traveling through the capacitor, overheating, or debris might be to blame.

How to fix: find the compressor – the thing attached to it with electrical leads is the capacitor. Use a multimeter to test it for continuity.

If there is no continuity, the capacitor is burned out and needs to be replaced. Fortunately, this part of the unit is relatively cheap.

Rheem Air Conditioners Troubleshooting – Reasons for Loud Noises


If the compressor is generating more noise than usual, then the thing is wearing out.

You wouldn’t necessarily need to replace the compressor as it might be able to work for a few more years, but if the noise is an issue, then have a professional replace it.

Fan Blade

Check the fan blade in the front and the one in the rear. If the fan blade is damaged, it might be rubbing against another part of the unit – this is what’s making the noises.

The only thing that you can do is replace it. 

Blower Wheel

Try wiggling the blower wheel. If it feels a bit too loose, then try to tighten it (replace the screw, if needed).

The blower wheel is still unstable? Then you would have to replace this part of the unit.

Blower Motor

If the fan blades look ok, then the problem might be with the blower motor bearings. Check them for wear and if they look a bit old, then (you guessed it) replace the blower motor.

How Do I Reset My Rheem Air Conditioner?

At one point in your life, you may need to reset your Rheem air conditioner. This usually happens because of a power outage.

  • Turn the unit off with the help of your thermostat.
  • Find the back of the air conditioning case – the reset button is located at the bottom, near the copper lines.
  • Press the button.
  • Set the thermostat back to your desired temperature (this will, most likely, restart the unit).

If these simple steps did not help, then you should definitely call a professional. Sometimes, power surges can destroy capacitors and damage other parts of the unit, so you better leave this job to a professional. 

How to Replace Your Rheem Air Conditioner Air Filter

How often you should replace your air filter would depend on a few different factors. In general, manufacturers recommend getting a new filter every 3 months or so. 

It is relatively easy to change the filter. 

However, do bear in mind that sometimes owners put the filter upside down or the other way round. Of course, in such a case, the filter won’t be able to fulfill its main functions, so do pay attention to the arrows and instructions. 

  • Turn the unit off.
  • The filter is usually located in the return air duct.
  • Slide the old filter out of the slot.
  • Replace the old filter with a new one (don’t forget to pay attention to the arrows that are printed on the filter).
  • Finally, turn the AC back on.