One of the most important tasks is to inspect and clean the condenser coils. An excessive amount of dirt on the coils increases the operating discharge pressure. Systems running with higher-than- normal discharge pressures reduce the life of the compressor, reduce its refrigeration capacity, and consume more energy.
As the running discharge pressure increases, so does the power consumed by the compressor. The power consumption of the compressor could easily increase 10% to 30% with a sufficient increase in its discharge pressure. The actual pressure will vary depending on the type of compressor, its application, and the refrigerant used. For the actual increase, you need to refer to the compressor’s performance data sheet.
The reduction in refrigeration capacity means the system will now need to run longer to refrigerate the same load, further increasing the power consumed by the compressor. With the combination of longer run times and increased power consumption, it is easy to see the importance of keeping the condenser coil clean and its operating discharge pressure within normal operating parameters.
There are several ways to effectively clean condenser coils. Coils that do not have a heavy buildup of dirt or grease can usually be cleaned with a good wire brush. Coils with a mild amount of buildup could be cleaned with a soapy water solution.
Coils with a heavy buildup of dirt or grease may need to be chemically cleaned. This would entail using some type of acidic or alkaline-based chemical. Both types of chemicals have advantages and disadvantages. It is best to consult with the manufacturer of either the equipment or the chemical for recommendations.
When cleaning a condenser coil, it is important to not damage the fins or the coil surface. A condenser coil can be easily damaged, and that could restrict the airflow through the coil, resulting in even higher discharge pressures than before the coil was cleaned.
If the coils need to be chemically cleaned, the technician should carefully follow the directions from the chemical manufacturer. The tech should make sure the coil has been thoroughly flushed with fresh water after applying the chemicals per the manufacturer’s recommendations. Chemicals left on the coil could easily deteriorate the fins’ surface and possibly the tubing itself.
There are no real specifications on the frequency of coil cleaning. It is solely based on the ambient conditions surrounding the coil. Some coils may need to be cleaned every month, while others may only need to be cleaned yearly or perhaps at even longer intervals. Each unit should be looked at on a case-by-case basis.
With the continued focus on energy usage today, it is important to keep the condenser coils clean, not only to reduce energy consumption, but also to extend the life of the equipment.
Marchese is owner of Arctic-Air Refrigeration in Pittsburgh, PA.
Publication date: 06/04/2001