DON’T REPLACE THAT DUCTWORK – RESURFACE IT!

Carlisle HVAC provides the best, longest-lasting duct sealing and coating options on the market. Hardcast’s RE-500 duct resurfacing product improves indoor air quality by coating the system against dirt and dust while providing a “like new” surface that is resistant to mold, mildew and fungi. RE-500 contains EPA-registered components that make it resistant to bacterial growth while providing a smooth, semi-gloss ﬁnish that facilitates improved airﬂow. A building’s ductwork can be resurfaced instead of replaced with RE-500 using a traditional airless sprayer, spray cart, paintbrush or robotic delivery system.

Reducing air leaks in duct systems plays an essential role to ensure efficient HVAC system operation. This keeps operating costs down and occupants comfortable. The duct tester equipment used to test for air leaks in duct work is made up of a calibrated fan, high precision manometer, tubing to connect the manometer to the fan, and flexible duct to connect the duct tester to the HVAC system. The technology applied to commercial duct testers has greatly improved over the past decade. What used to be a large blower bolted to a wheeled hand truck can now be easily carried by one worker in a case with a shoulder strap; all without sacrificing power. However, even with some of the most powerful duct testers out there, more fan power is needed for extremely large HVAC cabinets to reach a desired test pressure. Some of these cabinets can be the size of a mobile home, which is far too large for a single duct tester to handle. Some testers are making their own duct testers with a larger blower, though accuracy is greatly reduced and uncertainty is increased when this route is taken. The test pressure for commercial duct leakage tests varies from project to project. This pressure is typically specified by the mechanical engineer who designed the system. Test pressures typically range from 3 to 10 in. W.C. In order to pass the test, an air handler or air handler and trunk must be at or below a certain flow (CFM) at a given pressure (in. W.C.).