To manually defrost a frozen evaporator coil, technicians should:

• A. Use a heat gun to accelerate the melting of the ice.
• B. Pour hot water over the coil.
• C. Run the blower without power to the compressor.
• D. Use a hair dryer on the coil.

Answer: (A)

When manually defrosting an evaporator coil, you want to apply heat in a controlled, focused way to melt the ice quickly without introducing liquids or risking damage to the unit. A heat gun provides directed, adjustable heat that can be swept across the frost, raising its temperature rapidly and melting it without flooding electrical components or insulation. Pouring hot water can cause water to contact electrical parts and may lead to further icing or damage, while simply running the blower without heat won’t remove the ice since there’s nothing to melt it. A hair dryer could help, but a heat gun offers more heat and faster melting, making the defrost process more efficient.