Outside Ac Unit Tries To Turn On

Introduction

When your outside AC unit tries to turn on but fails, it’s a frustrating situation, especially during hot weather. This usually means the unit is receiving power but can’t fully start its cooling cycle. This could be due to several reasons, ranging from a simple electrical issue to a more complex mechanical problem. Addressing this quickly is important not only for your comfort but also to prevent potential damage to your AC system, which could lead to more costly repairs down the line.

Common Causes of Outside AC Unit Tries to Turn On

Here are some typical reasons why your outside AC unit might be struggling to start:

Dirty Air Filter: A clogged filter restricts airflow, causing the unit to overheat and potentially shut down.
Tripped Circuit Breaker: Overloaded circuits or faulty wiring can cause the breaker to trip, cutting power to the unit.
Faulty Capacitor: The capacitor provides the initial jolt of electricity needed to start the motor. If it’s weak or damaged, the motor won’t start.
Dirty Condenser Coils: When the outside coils are covered in dirt, leaves, or debris, they can’t release heat effectively, leading to overheating.
Frozen Evaporator Coil: Restricted airflow inside the house can cause the evaporator coil to freeze, stopping the cooling process.
Bad Contactor: This is a switch that sends power to the compressor and fan motor. A faulty contactor can prevent the unit from starting.
Overheating Compressor: The compressor is the heart of the system. If it overheats, it can shut down to protect itself.
Low Refrigerant: Low refrigerant levels can cause the compressor to work harder, leading to overheating and startup issues.

Symptoms Checklist

Look for these signs to better understand the problem:

The fan motor doesn’t spin at all.
You hear a humming sound but the unit doesn’t start.
The circuit breaker for the AC unit trips frequently.
The fan spins, but the air coming out isn’t cold.
You notice ice forming on the refrigerant lines.
The unit starts and stops repeatedly (short cycling).

How to Fix Outside AC Unit Tries to Turn On Step-by-Step Guide

Follow these steps to troubleshoot the issue:

Safety First: Turn off the power to the AC unit at the breaker box. This is crucial to avoid electric shock.
Check the Breaker: Go to your electrical panel and ensure the breaker for the AC unit is in the “on” position. If it’s tripped, reset it. If it trips again immediately, there might be a more serious electrical problem.
Inspect the Air Filter: Locate the air filter, usually inside the indoor unit. Remove it and check for dirt and debris. If it’s dirty, replace it with a new one.
Clean the Condenser Coils: Use a garden hose (on a gentle setting) to spray the outside condenser coils. Be careful not to bend the fins. You can also use a fin comb to straighten bent fins for better airflow.
Check for Obstructions: Ensure there are no bushes, weeds, or other obstructions blocking airflow around the outside unit.
Inspect the Fan: Check the fan blades for any physical damage or obstructions that could prevent them from spinning freely. Remove any debris carefully.
Look for Ice: Inspect the refrigerant lines coming from the indoor unit to the outdoor unit. If you see ice, this could indicate a frozen evaporator coil. Turn the unit off and allow the ice to thaw completely (this could take several hours).
Check the Contactor: (Advanced – Use Caution!) With the power OFF, visually inspect the contactor. It’s a small electrical switch inside the outdoor unit. Look for signs of burning or corrosion. Do not touch any electrical components while the power is on. If you suspect a bad contactor, it’s best to call a professional.
Reset the Unit: Some AC units have a reset button near the electrical box on the outside unit. Press it and see if it restarts the unit.
Turn the Power Back On: After performing all these checks, turn the power back on at the breaker box.
Observe the Unit: Monitor the AC unit’s behavior. Does it start up properly and run smoothly? If not, proceed to the next steps.
Run the AC for Several Hours: Check the vents inside after an hour or so. If they feel warm, you have a bigger issue and should seek a professional.

Fix the Issue Without Buying Parts

Many problems can be resolved without purchasing new components:

Cleaning: Regularly clean the air filter and condenser coils. This helps maintain proper airflow and efficiency.
Resetting: Sometimes, simply resetting the breaker or the unit itself can resolve minor issues.
Inspection: Routine visual inspections can help you identify potential problems early on. Look for signs of damage, leaks, or obstructions.
Maintenance: Schedule annual maintenance checks with a qualified technician. They can identify and address issues before they become major problems.

When Replacement Might Be Necessary

In some cases, replacement of a component or the entire unit might be necessary. Common failing parts include:

Capacitor: Estimated cost ranges from $50 to $200 (parts and labor).
Contactor: Estimated cost ranges from $80 to $250 (parts and labor).
Compressor: This is a major repair and can cost $800 to $2,000 (parts and labor). If the compressor fails, it might be more cost-effective to replace the entire unit.
Complete AC Unit Replacement: Estimated cost ranges from $3,000 to $7,000 (including installation). Consider this option if your unit is old (10+ years) and experiencing frequent problems.

Safety Warning

Follow these safety precautions:

Always turn off the power to the AC unit before performing any maintenance or repairs.
Avoid working on electrical components if you’re not comfortable with electrical work.
Wear gloves to protect your hands from sharp edges and debris.
Avoid working on the AC unit in wet conditions.
Call a qualified technician if you’re unsure about any aspect of the repair.

Tools You May Need

Here’s a list of helpful tools:

Screwdrivers (Phillips and flathead)
Wrench set
Garden hose with spray nozzle
Fin comb
Work gloves
Multimeter (for advanced troubleshooting use with caution)

FAQ

Here are some frequently asked questions:

Q: My AC unit hums but doesn’t start. What could be the issue? A: This often indicates a problem with the capacitor.
Q: The breaker keeps tripping when I turn on the AC. What should I do? A: This could be due to a short circuit or an overloaded circuit. Call an electrician to investigate.
Q: How often should I clean my AC unit’s coils? A: It’s recommended to clean the coils at least once a year, preferably before the start of the cooling season.
Q: Why is my AC unit freezing up? A: This is often caused by restricted airflow or low refrigerant levels. Check the air filter and call a technician if the problem persists.
Q: What can cause my compressor to overheat?A: Dirty coils, low refrigerant, or a failing capacitor can cause the compressor to overheat.
Q: How do I know if I have a freon leak?A: Common indicators include ice buildup on the coils, hissing sounds, and the system never getting cold. Call a professional.

Conclusion

Troubleshooting an AC unit that’s struggling to start can seem daunting, but by following these steps, you can often identify and resolve the issue yourself. Remember to prioritize safety and don’t hesitate to call a qualified technician if you’re uncomfortable with any aspect of the repair. With a little effort and attention, you can get your AC unit back up and running efficiently, keeping your home cool and comfortable.