Frozen Indoor Coil
If the evaporator coil in the indoor unit freezes up, you may have an airflow problem or a refrigerant leak. Turn the A/C completely off and allow the ice to melt. Meanwhile, inspect your system for possible airflow restrictions.
What Causes Frozen Evaporator Coils
- Clogged air filters. A dirty filter restricts airflow and allows dust to build upon the cooling coil, which interferes with heat transfer and can ultimately damage the fans and compressor. If your filter is dirty, replace it with a clean one before turning the A/C back on.
- Blocked return registers. These are the vents that don’t blow air, but rather bring air back into the equipment for conditioning. Remove obstructions like furniture, drapes, or rugs from around the return registers.
- Leaky air ducts. Make sure they are free from problems like kinks or collapsed sections. Check the seals between duct sections to ensure air isn’t escaping before it gets to the registers.
Turn the A/C back on once the coil has thawed and obstructions have been removed. If there are no airflow obstructions, you likely have a refrigerant leak, which must be addressed by a licensed and qualified professional.
Electric Control Failure
If a component of your air conditioner stops working, such as the outdoor or indoor fan or outdoor condenser, the likely culprit probably has to do with the electric control of the system. Unfortunately, this probably isn’t something you can fix yourself.
What Causes an AC Electric Control to Fail
Over time, the electrical controls that run the major components of the system can wear out or become corroded. Electrical connections also loosen over time, and terminals and wires become corroded. Call your trusted HVAC professional for a thorough exam of the electrical controls of the system.
Condensate Drain Clogs
During periods of high humidity, condensation drips from the evaporator coil in the indoor unit and is collected in the condensate pan beneath. A plastic tube leads from the pan to an indoor or outdoor drain.
What Happens If Your AC Drain Line Is Clogged?
If the pan or the AC drain line becomes clogged with debris, the water in the condensate pan will back up and, as a safety precaution, shut down your system.
How to Fix a Clogged Condensate Drain Line
- Bailout the water in the pan
- Check the drain for debris
- Check the terminal end of the drain tube as well, especially if it’s located outdoors
- If you don’t see any clogs, get a piece of smaller flexible tubing and run it through the drain tube from end to end
What Can a Dirty Air Filter Cause
- Dust buildup on the evaporator coil due to a clogged air filter prevents the optimum absorption of heat and reduces airflow.
- Dust buildup on other essential components like the fan and compressor can result in damage and premature failure.
- Restricted airflow caused by a dirty filter can overheat the system, causing damage and even shutting it down.
Inspect the air filter every month and replace it when it’s caked with dust.
Preventing Common A/C Problems
Annual preventive A/C maintenance will go a long way toward preventing all of these common A/C problems and more. A yearly tune-up extends the operating life of your system, increases efficiency to save you money on cooling costs, and reduces harmful emissions to lower your carbon footprint. While early spring is the ideal time to have your system tuned up, it’s highly beneficial no matter what time of year you schedule it.