Excessive draft can inflate the operating cost of heating appliances and create dangerous operating conditions. The ENERVEX Modulating Overdraft Control System (MODS) provides 100% overdraft control. It improves efficiency for any heating appliance, is designed compactly to save space and accommodates both condensing & non-condensing applications. It is listed to UL378 and standard for Draft Equipment for 1400°F. Reduce your fuel cost, improve your efficiency and reduce emissions with Enervex’s Modulating Overdraft Damper System.