The foam is applied directly onto the outer most row of the finned tubes. The concept of using foam is that it will not be susceptible to gravity; rather migrate through the fins and adhere to any obstruction.
Consequently, the fin foam remains on the accumulation working to softens & disperses the accumulation away from the fins. Once the accumulation is softened & loosened with fin foam’s proprietary cleaner, a high volume - low pressure water rinse is used to expel the remaining dirt off the equipment. Following are some features: