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ServiceMax Blog

Why Ice Might Form on Your Air Conditioner’s Evaporator Coil

frozen-glassIf you have some knowledge of how the modern air conditioner works, you may know it’s a refrigerant-based system, working in a similar fashion to a refrigerator. To providing cooling, both systems use chemical refrigerant to absorb heat from inside and move the heat to the outside air. This is why the condenser unit outside your house blows out heated air when the AC is working.

What neither system needs to work is ice. It’s easy to believe ice might be involved somehow—after all, the air conditioner is sending out chilled air—but it isn’t the case. Moving heat from one place to another using refrigerant doesn’t use ice. It shouldn’t create it either.

So seeing ice on my AC’s indoor coil isn’t normal?

Not at all. The reason this might happen is because of a reduction in how well the cold refrigerant moving through the coil and fins is removing heat from the air. If the refrigerant doesn’t warm up from heat transferred from the air blowing across it, it will remain below freezing. As water vapor condenses and water collects on the coil (a natural part of the cooling process), the cold refrigerant will freeze it.

The presence of ice will further impede how well the refrigerant can absorb heat, which means more ice. Ice will continue to form over the coil and fins until the air conditioner can’t remove any heat from the air, which means it will stop working as a cooling system. The ice can also warp and damage the coil.

What causes this to happen?

There are a number of reasons for the evaporator coil to struggle to absorb heat and trigger ice development:

  • Dirt and grime on the coil: Any dirt or other debris over the coil creates a insulating layer against proper heat absorption, causing ice. This is one of the reasons regular AC maintenance is so important during the spring. If technicians find the coil is dirty, they can clean it off.
  • Clogged air filter: We can never repeat this enough: the air filter for your HVAC system much be changed every 1 to 3 months. If it becomes clogged, the lack of warm air drawn into the system can lead to the coil freezing.
  • Leaking refrigerant: This is the biggest problem that can cause a frozen evaporator coil. If refrigerant escapes through leaks, there will not be enough refrigerant left in the coil to draw sufficient heat to warm the remaining refrigerant. The smaller amount of refrigerant will be too cold and cause ice to develop. Low refrigerant must be remedied ASAP, since it can inflict catastrophic damage to the compressor.

Seek the help of HVAC professionals

No, you can’t scrape off the ice to solve this problem. This can damage the coil and still won’t resolve the underlying problem. You must have professionals provide air conditioning system repair.

For the air conditioning repair in Winnetka, IL necessary to see your evaporator coil is cleared of ice—and the core problem addressed—contact our technicians. We offer 24-hour emergency service for when you need your cooling restored on the double.

Malek Heating & Cooling has served Chicagoland since 1998.

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