Selecting a coil cleaner is important since the cleaner must neutralize and remove deposits on the coil's surface. There are three types of cleaners: alkaline, acidic and surfactants. Which one is right for you?
Alkaline cleaners are most widely used in neutralizing acidic coil deposits and are one of the most common types of coil cleaners. The reaction of the cleaner with the coil and dirt causes a foaming action (oxides or hydroxides of aluminum) resulting in the stripping away of minute layers of the base alloy with the soil attached. These types of foaming cleaners are harsh and are usually labeled as corrosive. Usually, this type of cleaner contains sodium hydroxide or potassium hydroxide. These base ingredients are so harsh that they attack the metal, the coil coating and can cause serious injury. Some of these are even known to cause chemical burns on the skin.
The other concern when applying these cleaners is the ability to rinse. Most hydroxides tend to cling to the surface unless sufficient wetting agents have been added to the formula to reduce surface tension of the solution. If the solution does not have enough wetting agents and is not rinsed thoroughly from the surface, the residual material can settle at the fin/tube interface and continue to attack the fin.
Acidic cleaners are similar to the alkaline cleaners in stripping away or "etching" the metal. When cleaning with an acidic cleaner, you will notice that the surface usually looks brighter. However, it is not necessary to brighten the coil to remove corrosive deposits. The passive oxides on the fin surface are not a detriment to the fins function of heat exchange.
In the past, cleaners have included nitric, hydrofluoric, sufuric, or muriatic acids. These are extremely damaging to coil metallurgy and the environment and should be avoided except in an industrial environment.
Modern cleaners are much more compatible with the environment and usually have a base of phosphoric or citric acid. These too are labeled as corrosive and should only been used to neutralize caustic deposits or prepare metal surface for coating. Husky Coil Sheen is a phosphoric acid cleaner that we recommend for use on non-coated coils prior to coating. It is also recommended for use in coastal environments to remove and neutralize airborne sea salts that deposit on condenser coil surfaces.
Surfactant cleaners are the preferred method of cleaning your coil. Their foaming action reduces surface tension, penetrates dirt, emulsifies and dissolves the solids without attacking the base metal. They are free-rinsing and lift and remove deposits easily. They are safe and easy to apply, are environmentally friendly and rinse quickly. Surfactants are almost always non-corrosive.
Husky Coil Guard is is a highly concentrated surfactant cleaner that removes dirt, grime, insect residue, and airborne deposited corrosives without damaging the coil's surface. It is recommended for all Bronz-Glow coated coils and is the only cleaner that will protect your coating warranty. It is safe for both the applicator and the environment.