Ac Unit Not Kicking On Outside

Introduction

When your AC unit isn’t turning on outside (also called the condenser), it means your home isn’t getting cooled! This is a problem that requires immediate attention, especially during the hot summer months. It often leads to uncomfortable living conditions and can indicate a potentially bigger issue with your cooling system. Identifying the cause quickly can save you from expensive repairs down the road. Explore more in our Air Conditioner Troubleshooting 3 collection.

Common Causes of AC Unit Not Kicking On Outside

There are several reasons why your outside AC unit might not be starting:

• Tripped Breaker: The circuit breaker dedicated to the AC unit may have tripped due to an electrical surge or overload.
• Thermostat Issues: The thermostat might be set incorrectly, or it could be malfunctioning.
• Dirty Air Filter: A clogged air filter restricts airflow, causing the unit to overheat and shut down.
• Condenser Coil Blockage: Debris like leaves, grass, or dirt can block the condenser coils, preventing heat exchange.
• Capacitor Failure: The capacitor provides the initial jolt of power to start the motor. If it’s faulty, the motor won’t start.
• Contactor Problems: The contactor is an electrical relay switch. If the contactor fails, it will not send electricity to the fan and compressor.
• Frozen Evaporator Coil: Ice buildup on the indoor evaporator coil can prevent the outside unit from starting.
• Refrigerant Leak: Low refrigerant levels can trigger safety mechanisms that prevent the unit from running.
• Overheating: The unit may overheat and shut off as a protective measure.

Symptoms Checklist

Use this checklist to accurately identify the problem:

• The thermostat is set to “cool,” but the outside unit is silent.
• The indoor fan is blowing air, but it’s not cold.
• You hear a humming sound from the outside unit, but the fan isn’t spinning.
• The circuit breaker for the AC unit has tripped.
• Ice buildup is visible on the copper lines connected to the outdoor unit.
• The outdoor unit starts briefly and then shuts off.

How to Fix AC Unit Not Kicking On Outside Step-by-Step Guide

Follow these steps to troubleshoot the issue:

1. Check the Thermostat: Ensure the thermostat is set to “cool” and the temperature is lower than the current room temperature.
2. Inspect the Air Filter: Remove the air filter (usually located inside near the indoor blower fan). If it’s dirty, replace it with a new one.
3. Reset the Breaker: Locate the circuit breaker for the AC unit in your electrical panel. If it’s tripped (switched to the “off” position), flip it to the “off” position completely and then back to the “on” position.
4. Inspect the Outdoor Unit: Visually inspect the outside unit for any obvious debris, such as leaves, grass, or branches, blocking the condenser coils.
5. Clean the Condenser Coils: Turn off the power to the unit at the breaker. Use a garden hose (with a gentle spray nozzle) to clean the condenser coils from the outside in. Avoid using high pressure, which can damage the fins.
6. Check for Ice Buildup: Inspect the copper lines leading to the outdoor unit for ice. If ice is present, turn off the AC and allow the ice to melt completely. This could take several hours. Once melted, try running the AC again.
7. Examine the Capacitor (Visual Check ONLY): Remove the access panel to the outdoor unit (after turning off power at the breaker). Look at the capacitor (it’s a cylindrical component). If it appears bulging, leaking, or damaged, DO NOT TOUCH IT. This could indicate a faulty capacitor. Call an HVAC technician.
8. Check the Contactor (Visual Check ONLY): Locate the contactor inside the outdoor unit (after turning off power at the breaker). It’s a relay switch. Check if it is burned or damaged. If you notice any damage, DO NOT TOUCH IT. This could indicate a faulty contactor. Call an HVAC technician.
9. Ensure Proper Airflow Around the Unit: Make sure there’s at least 2-3 feet of clear space around the outdoor unit for proper airflow. Trim any shrubs or plants that are too close.
10. Check the Condensate Drain Line: A clogged condensate drain line can cause the unit to shut down. Locate the drain line (usually a PVC pipe) and ensure it’s not clogged. You can try clearing it with a wet/dry vacuum.
11. Restart the Unit: After completing these checks, turn the power back on at the breaker and try running the AC again.

Fix the Issue Without Buying Parts

Many issues can be resolved without needing to replace any parts:

• Regular Cleaning: Regularly clean the condenser coils and replace the air filter to maintain optimal airflow.
• Thermostat Recalibration: Some thermostats can be recalibrated. Consult your thermostat’s manual for instructions.
• Visual Inspection: Regularly inspect the unit for any signs of damage or debris.
• Proper Landscaping: Ensure adequate clearance around the unit by trimming nearby plants and shrubs.
• Resetting: Power cycling the unit may solve some temporary issues.

When Replacement Might Be Necessary

In some cases, replacement of parts or the entire unit may be necessary. The capacitor, contactor, and compressor are common components that can fail over time. Replacing a capacitor might cost between $100-$300, while replacing a contactor might be $150-$400. If the compressor fails, it’s often more economical to replace the entire unit, which can cost between $3,000-$7,000 depending on the size and efficiency of the unit. For more related activities, check out our Air Conditioner Loud Outside.

Safety Warning

• Always turn off the power to the AC unit at the breaker before performing any maintenance or inspection.
• Avoid touching any electrical components inside the unit unless you are qualified to do so.
• Be careful when using water to clean the condenser coils. Avoid spraying water directly into the electrical components.
• If you are uncomfortable performing any of these tasks, consult a qualified HVAC technician.

Tools You May Need

Here’s a list of basic tools that can be helpful:

• Screwdriver (Phillips and flathead)
• Garden hose with spray nozzle
• Wet/dry vacuum
• New air filter
• Work gloves

FAQ

Here are some frequently asked questions:

• Q: Why is my AC unit humming but not starting? A: This often indicates a problem with the capacitor or the compressor.
• Q: How often should I replace my air filter? A: It’s generally recommended to replace it every 1-3 months, depending on usage and air quality.
• Q: What should I do if I see ice on my AC unit? A: Turn off the unit and let the ice melt completely. Then, check the air filter and airflow.
• Q: How do I clean my AC unit? A: Power off the unit at the breaker. Use a garden hose to gently spray the condenser coils from the outside in. Be careful not to damage the fins.

Conclusion

Troubleshooting your AC unit yourself can save you time and money. However, if you’ve followed these steps and your AC unit is still not working, it’s best to consult a qualified HVAC technician. They have the expertise and tools to diagnose and repair more complex issues. Don’t hesitate to seek professional help to ensure your AC unit is running efficiently and safely!. Discover more free resources across our collection library.