When Do I Need To Service My Central Air Conditioner?
February 28, 2026
ML14XC1 Lennox AC: Reliable Cooling for Your Toronto Home
March 1, 2026When your central air conditioning system stops working, especially during a hot summer in Toronto or Richmond Hill, it can quickly turn your home into an uncomfortable space. At Alliance Energy Source, we understand how important a reliable cooling system is. As a family-owned HVAC company serving the GTA since 1999, we specialize in diagnosing and fixing AC issues quickly and efficiently.
Here are the top 5 reasons why your central AC may not be working—and what you can do about it.
1. Dirty or Clogged Air Filters
One of the most common reasons your central AC stops working is a dirty air filter. Over time, dust, dirt, and debris build up and restrict airflow.
Signs of a clogged filter:
- Weak airflow from vents
- AC running constantly without cooling
- Increased energy bills
When airflow is blocked, your system has to work harder, which can lead to overheating or even system failure.
Solution:
Check your air filter monthly and replace it every 1–3 months, especially during peak summer usage in the GTA.
2. Thermostat Issues
Sometimes the issue isn’t with your AC unit—it’s with your thermostat.
Common thermostat problems:
- Incorrect temperature settings
- Dead batteries
- Faulty wiring
If your thermostat isn’t communicating properly with your AC system, it won’t turn on or may run inefficiently.
Solution:
Ensure your thermostat is set to “cool” and the temperature is lower than the current room temperature. If the issue persists, it may need professional calibration or replacement.
3. Refrigerant Leaks
Refrigerant is essential for cooling your home. If your AC system is low on refrigerant due to a leak, it won’t be able to cool effectively.
Warning signs:
- Warm air blowing from vents
- Ice buildup on refrigerant lines
- Hissing or bubbling noises
Refrigerant issues are not DIY-friendly and require certified HVAC technicians.
Solution:
Call a professional like Alliance Energy Source to locate the leak, repair it, and recharge your system safely.
4. Electrical or Capacitor Problems
Your central AC relies on electrical components such as capacitors, relays, and circuit boards to function properly.
Symptoms of electrical issues:
- AC won’t turn on
- Frequent system shutdowns
- Clicking noises
These problems can be dangerous if handled improperly.
Solution:
If you suspect electrical failure, it’s best to turn off your system and contact a licensed HVAC technician immediately.
5. Frozen Evaporator Coils
Frozen coils can stop your AC from working altogether. This usually happens due to restricted airflow or low refrigerant levels.
Signs of frozen coils:
- Ice on indoor unit
- Reduced cooling performance
- Water leakage around the furnace
Solution:
Turn off your AC and let the coils thaw. Then, check your air filter and airflow. If the problem continues, professional service is required.
Why Choose Alliance Energy Source?
At Alliance Energy Source, we’ve been proudly serving homeowners across Markham, North York, Etobicoke, and the entire GTA for over two decades. As an authorized Lennox dealer, we provide top-quality HVAC services including AC repair, maintenance, and installation.
What sets us apart:
- Family-owned and operated since 1999
- Fast and reliable service
- Expert technicians
- Competitive pricing
- Customer-first approach
Final Thoughts
A malfunctioning central AC can be frustrating, but many common issues are preventable with regular maintenance and timely repairs. Whether it’s a clogged filter, thermostat issue, or refrigerant leak, identifying the problem early can save you time and money.
If your AC isn’t working properly, don’t wait until it completely breaks down.
📞 Call Alliance Energy Source today at 416-887-9065 for professional AC repair and maintenance services in Toronto and the GTA.
Stay cool, stay comfortable—and let the experts handle the rest!


