Furnace Turns On But Ac Does Not

Introduction

Finding that your furnace is working perfectly fine, pumping out heat when needed, but your air conditioner refuses to kick on can be a frustrating and uncomfortable situation, especially during hot weather. This problem often occurs when switching from heating to cooling seasons, and can make your home unbearably hot. Addressing this issue promptly is essential, not only for your comfort but also to prevent potential damage to your AC system and ensure efficient energy usage.

Common Causes of Furnace Turns On But AC Does Not

Here are some typical reasons why your furnace might be working but your AC isn’t:

• Thermostat Settings: The thermostat might not be set correctly to “Cool” or the desired temperature may not be low enough to trigger the AC.
• Tripped Circuit Breaker: The circuit breaker for the outdoor AC unit might have tripped.
• Dirty Air Filter: A clogged air filter restricts airflow, potentially preventing the AC from starting.
• Condenser Fan Issues: The outdoor condenser fan might be broken or obstructed, preventing heat from being expelled.
• Frozen Evaporator Coil: Ice can form on the indoor evaporator coil, stopping the AC.
• Refrigerant Leaks: Low refrigerant levels can prevent the AC from cooling.
• Contactor Problems: The contactor, an electrical switch that starts the AC compressor, might be faulty.
• Capacitor Failure: The capacitor, which helps start the AC motor, might be dead.
• Drainage Issues: A clogged condensate drain line can trigger a safety switch that prevents the AC from running.

Symptoms Checklist

Use these indicators to help identify the issue:

• Furnace blows hot air when set to “Heat.”
• No cool air blows when thermostat set to “Cool.”
• Outdoor AC unit (condenser) does not turn on.
• You hear a humming noise from the outdoor unit, but the fan doesn’t spin.
• Circuit breaker for the AC trips frequently.
• Ice formation on the refrigerant lines.
• Water leaks around the indoor furnace unit.

How to Fix Furnace Turns On But AC Does Not Step-by-Step Guide

Follow these steps to troubleshoot and potentially resolve the issue:

1. Check the Thermostat: Ensure the thermostat is set to “Cool” mode and the temperature is set a few degrees below the current room temperature.
2. Inspect the Air Filter: Replace a dirty air filter with a clean one to improve airflow.
3. Check the Circuit Breaker: Locate the circuit breaker panel and reset any tripped breakers associated with the AC unit.
4. Inspect the Outdoor Unit: Look for any obvious obstructions (leaves, debris) around the outdoor condenser unit. Clear any blockages.
5. Check the Condenser Fan: Ensure the fan blades are not obstructed and can spin freely. If it’s stuck, try gently nudging it with a stick (power OFF!) to see if it loosens.
6. Look for Ice Formation: Inspect the refrigerant lines leading to the indoor unit for ice buildup. If present, turn off the AC and allow the ice to thaw for several hours.
7. Check the Condensate Drain: Locate the condensate drain line near the indoor unit and check for clogs. You can try using a wet/dry vacuum to clear any blockage.
8. Turn Off and On Again: Turn the thermostat to OFF, then switch to AUTO. Wait 5 min, then set to COOL with an appropriately low temperature setting.
9. Inspect Wiring for Damage: Inspect the wiring near the outside unit; look for obvious signs of damage.
10. Check the Contactor: Look at the contactor on the side of the AC unit, is it broken or look obviously damage, can test by pushing it in but only with power off.

Fix the Issue Without Buying Parts

Many issues can be resolved without needing to purchase replacement parts:

• Resetting: Resetting the thermostat and circuit breakers is often the first and simplest solution.
• Cleaning: Cleaning the air filter and clearing debris around the outdoor unit can significantly improve performance.
• Recalibration: Some thermostats may require recalibration; consult your thermostat’s manual.
• Inspection Tips: Regularly inspect the outdoor unit for signs of damage or obstruction.
• Maintenance Basics: Routine cleaning and filter replacement are crucial for preventing future issues.

When Replacement Might Be Necessary

If the above steps don’t resolve the issue, replacement of certain parts might be necessary. Here are some examples with estimated cost ranges:. For more related activities, check out our Ge Window Ac Won T Turn On.

• Capacitor: A failed capacitor (a common problem) might cost $50 – $150 to replace.
• Contactor: A faulty contactor can range from $75 – $200 including labor.
• Refrigerant: Refrigerant recharge is around $200 – $600, depending on the amount required and type of refrigerant. However, it may be time to replace unit altogether.
• Complete AC System: If the compressor or other major components have failed, replacing the entire AC system can cost $3,000 – $8,000, depending on the size and efficiency of the unit.

Safety Warning

• Always turn off the power to the AC unit at the circuit breaker before performing any maintenance.
• Avoid working with electrical components if you are not comfortable or experienced. Call a professional.
• Be cautious when handling tools and avoid working in wet conditions.
• Never attempt to repair refrigerant lines or components. Refrigerant handling requires specialized equipment and training.

Tools You May Need

• Screwdrivers (Phillips and flathead)
• Wrench set
• Wet/dry vacuum
• Multimeter (for testing electrical components use with caution!)
• Flashlight

FAQ

Here are some frequently asked questions about AC problems:

• Q: Why is my AC blowing warm air? A: Could be low refrigerant, a dirty air filter, or a faulty compressor.
• Q: How often should I change my AC filter? A: Typically every 1-3 months, depending on usage and the type of filter.
• Q: My AC is making a loud noise; what should I do? A: Turn off the unit and inspect for loose parts or debris. If the noise persists, call a technician.
• Q: How do I prevent my AC from freezing up? A: Ensure adequate airflow by regularly replacing the air filter and keeping the outdoor unit clear of obstructions.

Conclusion

Troubleshooting your AC system can often lead to simple fixes that save you money. However, if you’ve exhausted these steps and the problem persists, don’t hesitate to contact a qualified HVAC technician. They have the expertise and tools to diagnose and repair more complex issues, ensuring your AC system runs efficiently and effectively. Attempting DIY beyond your skill level could cause further damage or create a safety hazard.