TinnerFlow™2nd YearRED · Stop / Get DirectionBlocked Bird Screen
A louver needs an open air path behind it. If another trade covers the opening, stop the cover-up and get the obstruction removed or redesigned before startup.
A fresh-air louver can look fine from the outside while being completely blocked behind the screen. If the sheathing, siding, or backing board covers the air path, the air handler can be starved and the building can pull negative pressure.
Verify the louver has an open path behind the full active area shown on the mechanical drawings. Stop cover-up work, document the obstruction, and coordinate the cutout or framing correction. Do not start the fan against a blocked louver.
Do not assume an exterior louver is functional just because the face looks installed.
A blocked intake can starve equipment, create building pressure problems, and damage the louver or fan.
Final direction belongs to the foreman, approved drawings/specs, manufacturer instructions, pressure/material schedule, employer policy, and AHJ/code requirements.