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Ice on the Air Conditioner: No, It Shouldn’t Be There

air-conditioning-unitHere’s a question we often hear from customers. In fact it’s a question any quality HVAC company will hear multiple times:

Hey, there’s ice on my air conditioner’s evaporator coil. Is that … supposed to happen?

It’s a good question. That people think to ask it in the first place is good sign. It shows they have an understanding that, even though air conditioners blow out chilled air when they’re running, ice is probably not a part of the cooling process. Or at least, it shouldn’t be.

This instinct is correct: when ice starts to appear on the indoor coil of a central air conditioner (i.e. along the evaporator coil), it means something is wrong. In most cases, you’ll need to call for air conditioning repair in Raleigh, NC or elsewhere in order to fix the problem—and sooner, rather than later.

What’s Wrong with Ice on the Evaporator Coil?

Answering this requires taking a closer look at how a central air conditioner (as well as a heat pump) operates. An air conditioner is a refrigeration-based system. It cycles refrigerant, a chemical blend that can transfer easily between liquid and gas states, between two sets of coils. The indoor coil, i.e. the evaporator coil, evaporates the cold refrigerant to absorb heat from the indoor air. This raises the temperature of the refrigerant up past freezing. The refrigerant, after moving through the compressor which heats it up even further, releases its heat to the outdoors through the outdoor condenser coil.

But what happens if the evaporator coil isn’t able to absorb enough heat to warm up the refrigerant? The refrigerant remains below freezing, and that causes the moisture along the coil to change to ice. And since the ice makes it even harder for the coil to absorb heat, the ice will continue to grow, starting a vicious cycle that eventually makes the AC unable to provide cooling at all.

Why Does This Happen?

There are a couple of reasons for the condenser coil to struggle with drawing heat out of the air and warming the refrigerant:

  • If the HVAC system air filter is clogged, that fan will draw an insufficient amount of warm over the evaporator coil. This is yet another reason why you need to regularly change the air filter on your HVAC system throughout the summer.
  • Dirt and grime across the coil create an insulating later, restricting heat absorption. During regular maintenance, technicians check on the evaporator coil to see if it needs to be cleaned. This is a friendly reminder to always schedule air conditioning maintenance from professionals before summer starts.
  • The biggest problem that can lead to a frozen evaporator coil is a drop in refrigerant levels because of a leak. With less refrigerant in the coil, the refrigerant won’t be able to absorb enough heat to warm the remaining refrigerant past freezing.

Don’t delay with contacting us to schedule air conditioning repairs when you see ice on your air conditioner. If the problem is with the refrigerant, the entire air conditioner is in danger of trouble with the compressor.

Comfort Master Heating & Air Conditioning, Inc. serves the Triangle Area of North Carolina. We offer 24-hour emergency service when you need your air conditioner repaired.

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