d7e42f72_ES__INC____Roofing_Terminology__VALLEY
(As it related to a passive ventilation system where the system is designed for air flow between intake and exhaust vents): A ventilation short circuit occurs when air is introduced into the ventilation system from an area higher than the intake vent thereby minimizing or defeating the effectiveness of the intake vent. One example can be a gable vent in a soffit-to-ridge ventilation system. Air intake from the gable vent can shor circuit the stack-effect draw of air through the soffit vents, and interrupt the thorough venting of the roof cavity. [VALLEY] 
VENTILATION SHORT CIRCUIT
ARMKO INDUSTRIES, INC. - Roofing Terminology
VALLEY