Patent ID: 7132017

Claim:
A method for cleaning an exposed heat exchanging coil, the method comprising the steps of: a. providing a low-pressure cleaning system having (i) a pressure source that creates movement of air, and (ii) a discharge tube with a first end connected to the pressure source so that air will pass from the pressure source into the discharge rube and a second end that allows air to exit out of the discharge tube; b. aiming the second end of the discharge tube at the heat exchanging coil; c. operating the low-pressure cleaning system to cause air to exit the second end of the discharge tube at a pressure less than about 50 pounds per square inch but greater than zero pounds per square inch at a velocity greater than about 180 miles per hour, and a volume of greater than 440 cubic feet per minute; and d. removing foreign particles from the heat exchanging coil by causing the exiting air to pass through the hear exchanging coil.