Why Your Air Conditioning System is Blowing Hot Air

Posted by Scott Mise | 06.23.2015

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When your A/C is blowing hot air into your Austin home, you’ll want to find the cause so the situation can be resolved fast. Review a list of common problems that can cause your A/C to blow hot air and decided if you can troubleshoot the issue or if it may be time to contact an HVAC professional.

Thermostat Setting

The easiest fix, which you may have already checked, is the thermostat. Check again to make sure the thermostat is on the “cool” mode and adjusted below room temperature. Also, be sure to check the thermostat wiring to ensure the wires are fastened securely to the terminals.

Condenser Coil

The condenser coil is positioned in the outdoor unit of a split-system A/C. If the condenser is dirty the heat exchange is blocked. Shut off the unit’s power at the disconnect plug then spray the sides of the unit with a foaming coil cleaner, followed by spraying with a garden hose. Continue to spray the entire unit until it is clean.

Evaporator Coil

The evaporator coil is often located on top of the furnace in an upflow system. You could have to remove some panels to access the evaporator. If there’s ice accumulation on the evaporator, turn the A/C to “fan” mode or turn the furnace on to help melt the ice. Before doing this, check the air filter and change it if it’s clogged with dirt. Poor airflow across the evaporator can create ice buildup. In addition, use the foaming coil cleaner on the evaporator. If ice returns, this is a good time to call your technician.

There are other causes for ice buildup, like an electrical problem or incorrect refrigerant charge. Your HVAC tech should handle those issues.

Compressor Problems

When you cleaned the condenser coil, you also happened to clean the compressor, which helps prevent overheating. Please note though that if you hear humming, grinding or rattling from the outdoor unit, turn the A/C off and call your technician.

To learn more about why your A/C is blowing hot air into your Austin home, contact Airco.