Technical directory · Filtration
Filter rack bypass
Air finding a path around the filter carries particles toward the blower and coil even when the filter itself looks clean.
What to observe
Look for clean streaks through dirty material, dust trails past the rack and a bowed filter under fan operation.
A field example
A bright clean streak through a dirty filter may mark a high-flow path at its edge. Matching the rack opening and closing the proper door matters more than choosing a more expensive media panel.
What the written work should say
Ask the technician to document how the rack and retaining door fit and whether any approved sealing work is proposed.
Where this task stops
Avoid taping over access or service openings to conceal a structural fit problem.