Why Your Air Conditioner May Be Blowing Hot Air

When the Arizona heat is in full force, the last thing you want to feel is a consistent blowing of hot air. This problem is more common than one might think—in fact, it’s one of the top reasons homeowners in Scottsdale and throughout the Valley call us for help. So, why might an air conditioner start to blow hot air? There are several potential causes, and some are more likely than others. While you should let a professional do the diagnosing, here are a few of the most common reasons.

Refrigerant leaks

Very often, we see air conditioners start to blow hot air because of refrigerant leaks. Refrigerant absorbs heat and plays a vital role in the cooling process. Without it, your air conditioner wouldn’t function at all. Refrigerant leaks often occur in either the indoor (evaporator) coils or the outdoor (condenser) coils. Leaks can also occur in the refrigerant lines that run between indoors and outdoors.

1. TXV

TXV stands for thermostatic expansion valve. Its job is to control the rate that liquid refrigerant flows into the evaporator. It does so by sensing the temperature of the refrigerant to determine how much the valve will let through. Refrigerant leaks and improper temperature readings can occur when the sensing bulb is loose, improperly attached, or the valve is stuck from contaminates.

2. Service valve

The service valve in your air conditioner houses ports that a technician uses to connect to the system for diagnostics and testing. If the O-ring deteriorates, or debris get stuck in the valve, it can begin to leak refrigerant.

What happens when you have a refrigerant leak?

When a loss of refrigerant occurs, it’s common to expect a reduced overall lifespan for the air conditioner, as well as a loss of performance. Despite what some contractors may tell you, you can’t fix refrigerant problems by simply adding more refrigerant. The only solution is to repair the leak at its source, or to consider a replacement if the leak isn’t fixable.

Whether or not your refrigerant leak can be repaired depends on where it’s located within the air conditioner. In some cases, replacing the coils or the system is a more economical choice when you factor in parts and labor costs. At Larson, we’ll take special care to ensure we walk you through all potential outcomes and options when it comes to your air conditioner’s refrigerant leak. We want you to make the best decision for you and your home. 

Run capacitor problems

A run capacitor sends energy to the motor that powers your air conditioner throughout its cooling cycle. Over time, capacitors can wear down and start to weaken. Think of them as batteries that gradually lose power. With a weak capacitor, your air conditioner won’t function like it should. The motor or compressor may struggle to start up or won’t start at all. When capacitors go bad, it’s also common for air conditioners to start blowing hot air. Other problems you may encounter with a bad run capacitor include:

  • Your air conditioner won’t turn on at all
  • Your air conditioner turns off prematurely
  • Your air conditioner takes a while to start

Replacing a run capacitor is a common repair and if a bad run capacitor was to blame for your air conditioner blowing hot air, then replacing it should restore the cool, comfortable air you want.

Frozen evaporator coils

We know what you’re thinking—how is it possible for part of my air conditioner to freeze when its 100 degrees outside? However, it is very possible (and common) for evaporator coils to freeze because of insufficient airflow or refrigerant leaks.

1. Insufficient air flow

Very dirty filters, closed/blocked vents and ducts, a malfunctioning fan, and a dirty coil can all compromise airflow and cause your evaporator coil to freeze. Having your coil cleaned regularly is recommended. At Larson, we include an evaporator coil clean as part of our premium maintenance plan.

2. Refrigerant leaks

We discussed refrigerant leaks above, but as you can see, there are still more problems that can arise when your refrigerant levels are low. Low refrigerant causes pressure to drop within the coil, allowing moisture to accumulate and (eventually) freeze on the coil. Addressing the root cause of the leak—and not simply “topping off” the system with more refrigerant—can fix the problem.

Dirty condenser coils

Condenser coils are located outdoors and they are not well-protected from the elements. That means dust from monsoons, dirt from your yard, and general grime can build up on the coils. When this occurs, the coils are unable to release as much heat as they need to, which can lead to your air conditioner blowing warm air.

Clean condenser coils help your air conditioner work at its best, which is why we include an outdoor coil cleaning as a perk for our maintenance plan members.

Leaking ducts

In some cases, your air conditioner may be blowing warm air because leaks throughout your ductwork are allowing the cooled air to escape before it reaches its destination. If you suspect your ducts are to blame, Larson’s technicians can test your existing ductwork and recommend repairs, sealing, or replacement.

Get to the bottom of your A/C problems with Larson

If your air conditioner is blowing hot air, no air, or something else entirely, we’re here to help fix the problem. Call (480) 428-0600 or schedule online to book an appointment today.

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