How to clean AC condenser

There are two parts to a home air conditioner system, ok, so there are a lot more than two, but there are two big components that require periodic maintenance.  One of the maintenance tasks that you as a homeowner can do is to keep the condenser unit (the outside component) and the evaporating unit, (the inside component) clean.

We’ll take you through the steps to clean the condensing unit.

Identifying the parts

The condensing unit has three main parts, the compressor, fan, and condenser.

These combined units are responsible for dissipating the heat generated in an air conditioning system. It might seem like an oxymoron, but to cool a house, you have to generate heat. It’s the exchange of hot and cold that allows the Freon inside the system to work, and by default cook your home.

The compressor moves the Freon between the condenser and the evaporator inside to chill the air.

The condenser acts as a radiator to disperse the heat generated in the cooling process to the outside air. It acts just like the radiator in your car.

The final component is the fan. It generates airflow over the condenser to keep the unit cool, prevents overheating, and is the only sound you often hear in a functioning air conditioning unit.

These three components all work with gas, either ambient air or Freon. When the airflow is impeded, you can have problems that quickly escalate from a free, easy fix to perhaps thousands of dollars if your air conditioning system suffers from heat damage.

The Grill

The condensing unit has to have unimpeded airflow. The fan pulls the air down from above, but it then flows out the four sides of the condenser enclosure.

Typical large sized home air conditioner – Photo by Randy Tucker

The most common problem on a condensing unit comes when the screen on the grid surrounding the assembly becomes clogged. The unit sits outdoors so it is susceptible to debris, lint, tree cotton, and weeds growing up around it. All of these can affect airflow.

Morning glory vines before removal – Photo by Randy Tucker

Morning glory, also known as bindweed is one of the worst. The tiny vines climb up the screen, grow out and block airflow.

A second big cause of blockage, at least out west, is cottonwood lint. The cotton that grows and then releases into the air from female cottonwood trees creates clouds of wind-blown lint. These clumps follow the air currents and often end up plugging the condenser assemble.

Remnants of vines growing on condenser unit – Photo by Randy Tucker

The good news is that this is easy to fix.  Physically pulling out the lint and debris by hand is the first step. The second is to cut the roots of any climbing vines that work their way up the assembly. They’ll dry out quickly and disappear without roots.

The third step is to thoroughly rinse the screen with a high-pressure garden hose, or better yet, a pressure washer. This is usually done from the outside without removing the fan.

Not the cooling and return lines connecting the condenser and evaporative units – Photo by Randy Tucker

If it’s severely plugged you may have to unscrew the eight to 12 sheet metal screws holding the fan assembly on the frame.  Carefully lift the fan, making sure you don’t disconnect any wires. If you have to remove wires, take a cell phone pic of the wires so you’ll remember where they go when you put everything back together.

With the fan removed, and the air conditioner turned off. Wash out the inside of the screen.

Power control for condensing unit – Photo by Randy Tucker

Put everything back together and you’ll be good to go.