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WHY IS THE AC NOT BLOWING COLD AIR?

From very simple issues like a thermostat set incorrectly or a dirty filter, to a more complex situation that requires replacing components, there are a wide variety of reasons why you may find your air conditioner not lowering the temperature in the house, even while still running.  We’ll outline some items you should check before calling a professional here. 

THERMOSTAT IS SET INCORRECTLY

When you notice your home getting a little hotter than normal, first check the thermostat settings. Be sure it is set to cool. If the thermostat is set to cool, check the temperature setting to be sure someone hasn’t changed it. If it is off, set to heat, or set for constant fan (sometimes simply labeled “on”), switch it back to cooling operation. After the system kicks on, wait a few minutes, then check for cold air blowing from the registers. If it’s cold, problem solved! If not, move on to the next troubleshooting tip – checking the air filter.

DIRTY AIR FILTER

Your AC system may include an air filter located in or around the indoor air handler unit. The filter catches dirt, dust and other airborne particles as they enter the air handler unit. It keeps the components inside the system cleaner and operating more efficiently and can help keep the air in your home cleaner as well. A dirty air filter can block airflow and reduce cooling to your home. In more extreme cases, it can cause the system to shut down completely. 

If your thermostat checks out and you still don’t have cool air, locate your system’s air filter, turn the system off, remove the filter and inspect. If, after you are satisfied that you have a clean air filter and your central air conditioner does not cool your home, you’ll have to dig a little deeper to locate the problem.

CONDENSER UNIT IS BLOCKED

Your central air conditioning system likely includes an outdoor condenser unit. The exterior of the condenser unit features a large outdoor coil, which wraps most of the way around the outside of the unit. The coil includes a series of thin metal “fins” which are spaced very tightly together. If your air conditioner is running, but not lowering temperatures inside, one issue could be a blocked or clogged condenser coil. When operating correctly, the condenser fan draws air into the outdoor unit through the condenser coil to pull heat energy out of your home. Dirt, grass and other airborne debris can accumulate between the fins, clogging the coil. A dirty coil can lead to reduced energy efficiency, lack of cool air from the registers, or in extreme cases, complete system shutdown or damage to the compressor from overuse. You can attempt to clean the coil by clearing away debris, carefully vacuuming the coil with a brush attachment or rinsing gently with a hose. If your system still isn’t cooling, it’s probably time to call a professional. 

DAMAGED HEAT PUMP

In some cases, your outdoor unit might be a heat pump. A heat pump looks just like an AC unit, with some different components inside that allow it to both cool and heat your home. In cooling operation, it operates just like an air conditioner system’s condenser unit and is subject to the same issues – dirty, clogged coil, frozen coil, refrigerant leaks, compressor malfunctions, etc. If your heat pump system isn’t cooling, check thermostat settings, the air filter, and the condenser unit for previously described issues. If everything checks out and you’re still sweating inside, call your local HVAC professional. 

EVAPORATOR COIL IS FROZEN

The indoor component of your central air conditioning system will include an evaporator coil. If your indoor unit is a furnace, the evaporator coil sits in its own cabinet, outside the furnace. If the indoor unit is a fan coil (typically as part of a heat pump system), the evaporator coil sits inside the fan coil cabinet. Warm indoor air passes through the evaporator coil where heat energy and humidity are removed from the air. Cooler, more comfortable air is then circulated back to your home. Signs of a frozen evaporator coil include:

  • Frost forming on the copper refrigerant tubing coming from the coil cabinet
  • Inadequate cooling
  • Excessive condensate drainage near your indoor unit
  • In extreme cases, frost forming on exterior refrigerant tubing or the outdoor unit

Because accessing the evaporator coil is difficult, resolving issues associated with a frozen evaporator coil are best handled by an HVAC professional.

REFRIGERANT LEAK

Refrigerant is a chemical that is critical to the cooling process. It flows through the system’s indoor and outdoor coil, changing from liquid to gaseous form, drawing heat energy and humidity from indoor air and releasing it outside. Depending upon its severity, a refrigerant leak can contribute to your AC system not blowing cold air, your system may run for longer periods of time without adequately cooling your home, or it can cause a damaged or failed compressor and complete system shutdown.

Checking and resolving issues involving refrigerant levels in your system is another job for your local HVAC professional. 

TRIPPED CIRCUIT BREAKER

Testing a circuit breaker for proper operation that controls a central AC unit is the same process as with any circuit breaker. That safety device must be able to conduct electricity through the switch, as well as trip the unit out of the circuit when an unsafe condition occurs.  To check your breakers, locate your indoor breaker panel, open breaker panel and check to see if any breaker, ac specifically, is tripped.  If so, set back to ''on'' position. 

CONTACT A HVAC PROFESSIONAL

Thermostat not reaching the set temperature? If you reach this conclusion and you’ve exhausted the options outlined previously, it’s time to call a HVAC professional.  It’s important for your comfort, but also for the health of your AC system. **Continuing to run your AC when it’s not properly cooling your home can take a minor issue and turn it into a major component failure or system replacement.**  If you are having issues with your AC/Cooling system, TURN YOUR AC OFF and call ADE Heating and Cooling today, at 609-693-6050!
 

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