There are several cleaning solutions in the market suitable for condensers. They are primarily alkaline or acid, about the same price and about equally effective. The alkaline is preferred since it is less destructive. Nevertheless, it should be cleaned up promptly if it runs off onto the flooring.
Additional care must be taken when applying these chemicals to the cooling fins of a condenser. The condenser fan(s) may have to be covered to prevent moisture from entering the motor(s). Once the solution is applied, the dirt, grease, and lint begin to boil and steam. This indicates it is working.
After the solution is given a chance to work for a while, it can then be easily removed with a high-pressure stream of air. Most technicians carry a cylinder of CO2 (carbon dioxide) or nitrogen in their trucks. It is an excellent tool to clean a linted condenser very quickly.
For cleaning condensers on residential units, all you need is a good long-bristled brush and a vacuum cleaner.
Very often, especially in commercial units, a failure to cool properly can be due to a dirty or linked condenser. Even if the condenser appears clean on the outside, dirt accumulated at the base of the fins and coil can prevent proper heat exchange and keep the unit from cooling.
Furthermore, particularly in the case of roof-mounted condensers, make certain they are protected from direct exposure to the sun and have adequate shade to assist in the cooling process. A unit left exposed to the sun absorbs so much heat that it becomes incapable of transferring heat necessary to change the hot vapor refrigerant back to its liquid state. When this happens, the head pressure will rise above normal. The temperature will
never drop low enough to satisfy the cold control causing the compressor to run continuously. Eventually, the overheated compressor will cycle on overload. Do not rely on natural shading (taller buildings, trees, etc.). It will be necessary to build a structure over the condensing unit if one is not already provided.
The symptoms are often misdiagnosed as a bad compressor or a weak overload protector.