Rheem Air Conditioner Not Cooling

When your Rheem air conditioner fails to cool your home, it can be frustrating, especially during hot summer months. However, before you call a technician, there are several steps you can take to diagnose and potentially fix the issue yourself. This guide will walk you through a systematic approach to troubleshoot your Rheem air conditioner not cooling.

1. Check the Thermostat Settings


Check the power supply to your Rheem air conditioner. Ensure that it is receiving electrical power. You can do this by:

a. Checking the Circuit Breaker

Inspect the circuit breaker panel in your home. Look for any tripped breakers related to your air conditioner. If you find a tripped breaker, reset it and see if the air conditioner starts working again.

b. Testing the Disconnect Switch

Near your outdoor unit, there should be a disconnect switch. Ensure it is in the “ON” position. Sometimes, this switch is accidentally turned off.

3. Clean or Replace Air Filters

Dirty or clogged air filters can restrict airflow, making your air conditioner less effective. To clean or replace the air filters:

a. Locate the Air Filter

The location of the air filter may vary depending on your specific Rheem model. Commonly, it’s in the air handler unit or near the return air grille.

b. Clean or Replace the Filter

If it’s a reusable filter, remove it and clean it according to the manufacturer’s instructions. If it’s a disposable filter, replace it with a new one.

4. Inspect the Outdoor Unit

The outdoor unit of your Rheem air conditioner plays a crucial role in cooling your home. Check for the following:

a. Clear Debris

Inspect the area around the outdoor unit. Remove any debris, leaves, or obstructions that could be blocking airflow.

b. Listen for Unusual Sounds

Turn on the air conditioner and listen for any unusual sounds coming from the outdoor unit. Grinding or squealing noises might indicate a problem with the fan motor or compressor.

5. Monitor the Cooling Cycle

After you’ve checked the thermostat, power supply, air filters, and outdoor unit, allow your air conditioner to run for a while. Monitor the cooling cycle to see if the air coming from the vents gradually gets cooler. If it doesn’t, there might be a refrigerant issue or a problem with the compressor, which requires professional repair.

6. Call a Professional

If none of the above steps resolve the issue, it’s time to contact a qualified HVAC technician. They have the expertise and tools to diagnose and repair more complex problems, such as refrigerant leaks, compressor issues, or electrical problems.

7. Check Refrigerant Levels

Refrigerant is the lifeblood of your air conditioning system, and low levels can result in poor cooling performance. Checking refrigerant levels is a task best left to professionals due to the potential health and environmental hazards involved. Signs of low refrigerant levels may include:

  • Ice buildup on the indoor or outdoor unit.
  • A hissing sound near the refrigerant lines.
  • Reduced or warm airflow from the vents.

If you suspect a refrigerant issue, it’s essential to contact a licensed HVAC technician. They can identify the cause, repair any leaks, and recharge the system with the correct refrigerant.

8. Examine the Evaporator and Condenser Coils

Over time, the evaporator and condenser coils in your air conditioner can accumulate dirt and dust, reducing their efficiency. This can result in decreased cooling capacity. Here’s how to address this issue:

a. Evaporator Coil

The evaporator coil is typically located in the air handler unit. If it’s dirty, it can impede heat exchange. A professional technician can clean the coil with specialized cleaning solutions.

b. Condenser Coil

The condenser coil is located in the outdoor unit. Dirt and debris can accumulate on its fins, hindering heat dissipation. Gently clean the coil with a soft brush or use a commercial coil cleaner. Ensure the power is off before attempting any cleaning.

9. Evaluate Ductwork

Leaky or poorly insulated ductwork can lead to cool air escaping before it reaches the rooms in your home. Here’s what you can do:

a. Check for Leaks

Inspect your ductwork for visible leaks or gaps. Seal any openings with duct tape or mastic sealant.

b. Insulate Ducts

If your ducts run through unconditioned spaces like attics or crawlspaces, make sure they are adequately insulated to prevent heat gain.

10. Assess the Age and Condition

The age and overall condition of your Rheem air conditioner can significantly affect its performance. If your unit is older and has been experiencing frequent issues, it might be time to consider replacing it with a more energy-efficient model. Newer systems often provide better cooling performance and lower energy bills.

11. Regular Maintenance

Prevention is often the best remedy. Consider scheduling regular maintenance for your Rheem air conditioner. An annual or bi-annual tune-up by a qualified technician can catch potential problems early, ensuring your system operates efficiently and reliably.


Common Causes of Rheem Air Conditioner Not Cooling

CauseDescriptionSymptomsTroubleshooting StepsSolution
Dirty Air FilterClogged filter restricts airflowWarm air, reduced flowReplace or clean the air filterRegularly replace/clean filters
Refrigerant LeakLoss of refrigerant gasNo cooling, hissingLocate and repair the leakRecharge refrigerant
Thermostat IssuesFaulty thermostat settings or wiringIncorrect temperatureCheck thermostat settings and connectionsReplace or rewire thermostat
Frozen Evaporator CoilAccumulated ice on the coilReduced airflowTurn off the AC to thaw, identify root causeAddress underlying problem
Electrical ProblemsWiring or capacitor issuesNo power, erraticInspect wiring, test capacitorsReplace faulty components
Blocked Condenser CoilDebris obstructing the condenser coilInefficient coolingClean the coil, remove obstructionsRegular maintenance
Low Refrigerant ChargeInsufficient refrigerant in the systemInsufficient coolingLocate and fix the leak, recharge refrigerantProfessional service required
Faulty CompressorMalfunctioning compressorLoud noises, no coolingTest compressor operation, replace if neededReplace compressor
Ductwork ProblemsLeaks or blockages in ductsUneven coolingInspect and seal ducts, remove obstructionsRepair or replace ductwork
Inadequate InsulationPoor insulation in the homeInefficient coolingImprove insulation, seal gapsHome insulation improvements

DIY Troubleshooting Steps for Rheem AC Not Cooling

ProblemDescriptionTroubleshooting Steps
Not CoolingAir conditioner isn’t producing cool air1. Check thermostat settings and mode.
2. Inspect and clean the air filter.
3. Ensure windows and doors are closed.
4. Clear obstructions around the condenser unit.
5. Check circuit breaker and reset if necessary.
6. Remove debris from the condenser coil.
7. Allow time for the unit to cool (if frozen).
8. Verify the ducts are not blocked or leaking.
9. Check for signs of refrigerant leaks.
10. Test the thermostat for proper operation.

Signs of Refrigerant Leak in Rheem AC

Hissing NoiseAudible sound of refrigerant escaping.
Reduced CoolingAir conditioner produces less cool air.
Icing on Copper LinesIce formation on the copper refrigerant lines.
High Energy BillsIncreased energy consumption without cooling.
Oil StainsOily residue around AC components.
Warm AirAir from vents is warm or room temperature.
Long Cooling CyclesAC runs for extended periods without cooling.
Frost on Evaporator CoilFrost buildup on the indoor evaporator coil.
Bubbling or Hissing atAudible sounds near the refrigerant lines.
Refrigerant Lines

 Recommended Maintenance for Rheem AC

Maintenance TaskFrequencyDescription
Clean/Replace Air FilterEvery 1-3 monthsImproves airflow and efficiency.
Check ThermostatAnnuallyEnsure accurate temperature control.
Clear CondenserAnnuallyRemove debris around the outdoor unit.
Inspect DuctworkEvery 2-3 yearsLook for leaks, blockages, or damage.
Professional Tune-upEvery 1-2 yearsComprehensive inspection and maintenance.

When to Call a Professional for Rheem AC Issues

Refrigerant LeakRefrigerant requires specialized equipment to handle.
Compressor FailureComplex repair or replacement task.
Electrical ProblemsHigh voltage components should be handled by experts.
Ductwork ReplacementSignificant duct repairs or replacements needed.
Major System MalfunctionsUnusual noises, odors, or persistent issues.


In summary, troubleshooting a Rheem air conditioner not cooling involves a combination of simple checks and more complex diagnostics. While you can handle basic tasks like thermostat adjustments, filter cleaning, and clearing debris from around the unit, many issues require the expertise of a professional HVAC technician. Regular maintenance and prompt attention to problems will help keep your Rheem air conditioner operating at its best, ensuring your home remains comfortably cool during hot weather.

Rheem Air Conditioner Not Cooling

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