Why Is My AC Blowing Warm Air?

When it’s already hot outside, the last thing you want is your AC blowing warm air into your home. This is one of the most common AC problems in summer for homes in Tennessee, and our team at Hometown Plumbing, Electrical & HVAC has seen it countless times.  Let’s explore the most common reasons you may experience this issue, when you can troubleshoot the problem yourself, and when you should call a professional.

Tripped Circuit Breaker

Many AC configurations require two circuit breakers: one for the outdoor condenser unit and one for the indoor blower. The outdoor unit’s breaker can trip, disabling the cooling while the blower continues to function. Check the breaker, and if it has tripped, reset it once. If it trips again, don’t keep resetting it. Instead, call us for AC repair services. Recurring trips may indicate a compressor malfunction, and repeated resets can actually lead to permanent compressor damage.

Incorrect Thermostat Setting or an Electrical Issue

Check your thermostat to verify an appropriate temperature setting. Make sure the thermostat isn’t in HEAT mode or that you have the blower set to ON. To be safe, you can power cycle your thermostat and check for any firmware and software updates.

The problem could be a dirty or malfunctioning thermostat, in which case you’ll need an HVAC technician. An AC blowing warm air can also indicate an electrical problem beyond the thermostat.

• Worn wire
• Failed capacitor
• Faulty control board
• Burned-out contactor

Airflow Restriction

Adequate airflow is essential to an AC system’s refrigeration process. If there’s an obstruction, this can undermine the cooling process and lead to warm air blowing.

If you recently switched to a new filter, check its MERV rating. If the rating is too high for your system, it won’t allow enough air through the supply vent. You should also check the filter to make sure it’s not clogged with dust and other debris. If it is, replace it with a fresh one, as this has the same effect as using a high-MERV filter.

You should also check the outdoor unit. If there’s a buildup of leaves, branches, and other debris, it can restrict airflow to the condenser coil.

Dirty Evaporator or Condenser Coils

An AC system uses coils to move heat energy from inside to outside. Over time, those coils can accumulate grime that serves as an insulator. When the buildup gets too thick, it impedes airflow through the system. You can avoid this problem by scheduling AC tune-ups early in the spring, before you need to cool your home. If you skipped AC maintenance this year, then there’s a high chance this could be the problem.

Low Refrigerant Pressure

Your AC needs the refrigerant pressure in a certain range in order to function properly. It’s important to note that AC systems do not consume refrigerant over time. If pressure is too low, then that usually means it’s leaking from one or more pinholes in the lines. It’s very difficult for a homeowner to detect whether or not they have a refrigerant leak. That’s why it’s crucial to call an HVAC technician for an AC repair near you as soon as you notice potential signs of a refrigerant leak.

• High indoor humidity
• Irregular system cycling
• Hissing or bubbling sounds
• Elevated energy consumption
• Ice on the evaporator coil or refrigerant line
• Excessive ponding water near the outdoor unit

Outdoor Condenser Unit Not Running

If you can’t hear the outdoor unit but the blower is on, this is the cause. This can happen even without tripping the outdoor unit’s circuit breaker. It could be that the condenser fan has stopped functioning, or the compressor may have seized up. If you have a heat pump, a third possibility is that the reversing valve has seized up in the heating position.

Expert AC Diagnostics & Repairs Throughout Knox and Washington Counties

Hometown Plumbing, Electrical & HVAC is a family-owned and -operated HVAC company with locations in Johnson City and Knoxville, TN. If your air conditioner isn’t cooling your Tennessee home, it’s urgent that you call us right away. Delays can result in unsafe summer conditions, high electricity bills, bigger repair costs, and permanent AC system damage. Our company has technicians on call for emergency HVAC repair in Tennessee. We also provide seasonal tune-ups and a Total Care Club that can help prevent AC malfunctions.

To schedule an appointment for an AC repair near you in the Johnson City area, contact our team today.