How to use an acid-based coil cleaner.
When you need to clean the indoor (evaporator) or outdoor (condenser) refrigerant coils, you should use the right detergent for the type of coil you are cleaning. Though there are many different types of coil cleaners, they all belong in two categories: acid based or non-acid based. An acid-based coil cleaner should only be used on condensers. Condenser coil cleaners are premixed or concentrated. Concentrated cleaners should be diluted with water (as the manufacturer directed) in a low-pressure sprayer. Do not apply acid-based, concentrated coil cleaner directly to coil! If not fully flushed, it could cause corrosion to other components and wires in the unit. When using an acid-based cleaner always use gloves and eye protection.
Shut the outdoor unit off at the service disconnect or circuit breaker. If the unit would come on while cleaning, back away from the system! The spray from the fan could get on you and burn you! Apply as directed by the manufacturer. Spray on mixture from the top to the bottom, until the coil is saturated.
If the coil is very dirty, the top of the unit may need to be removed and sprayed on both sides. Let the chemical do its job. Do not use any type of tool on the coil during this process, you can easily cause a refrigerant leak!
Flush coil thoroughly with a water hose. Starting at the top and work the spray down to the bottom of the coil. You can use a pressure washer, but make sure it is set for under 90 psi. A water hose or pressure washer nozzle set too high will damage the fins.
Aways take precautions when using an acid-based refrigerant coil cleaner. The runoff will likely kill any vegetation near the unit and can discolor siding or wood. Be prepared to rinse thoroughly and rinse again.
