What Are Condenser And Evaporator Coils And How Can Problems There Thwart Your HVAC System

Your central air conditioning system consists of an outdoor condensing unit and indoor air handler that each have a series of parts essential to the cooling process. Both the outdoor and indoor segments of the unit contain a set of coils that work to help ensure the chemical refrigerant keeps moving through the system.

The condenser coils outside and evaporator coils inside play such an important role that problems with either coils can thwart your air conditioning system. What are the condenser and evaporator coils and what problems can occur?

Condenser and Evaporator Coils Explained

The condenser coils in the condensing unit receive compressed refrigerant gas that is supplied by a motorized compressor. The coils are designed to conduct a phase change that makes the gas into a liquid. The change, which causes the coils to become warm, makes it possible for the now liquid refrigerant to travel inside the house, into the air handler, and into the evaporator coils.

The evaporator coils then work in the reverse of the condenser coils and change the liquid refrigerant back into a gas. The change causes the coils to become cold, which is how the ambient air circulating into your house becomes cold and makes your life more comfortable.

Potential Coil Problem: Dirt Buildup Thwarts Efficiency

The condenser coils exist inside of a grated unit that can allow dust and dirt to adhere to the coils. The evaporator coils become moist during the phase change, which makes those coils an easy target for dirt buildups. If either set of coils becomes overly dirty, the phase change process can become impaired and eventually start to cause an efficiency loss in your HVAC system.

You can clean the coils by first making sure the power is off to the unit you're working on. For the condenser coils, clean with a hose pointed outwards so you don't flood the bottom of the unit. For the evaporator coils, use a no-rinse foaming cleanser and follow the instructions.

If the coils still look dirty or damaged, call in an air conditioning services company to fix the problem.

Potential Coil Problem: Overheating or Freezing

The condenser coils become warm during the phase change and the evaporator coils become cold but swinging too far towards that temperature direction can cause problems.

If the condenser coils become overly hot, a motorized fan is meant to cool things down. But if the coils become too hot for the fan to counteract, or the fan itself has an operational problem, the condensing coils can become so hot they trigger the system's safety shutdown. Your unit will suddenly start shutting down unexpectedly and you won't be able to reach your desired indoor temperature.

Evaporator coils can become overly cold and freeze. The frozen coils won't allow following passes of refrigerant to convert properly. And the thawing freeze can cause the drain pan at the bottom of the air handler to overflow.

If you have either of these temperature issues, contact an air conditioning services company because the problem is likely with the refrigerant.