Opening drawing room air back to air-handling equipment.
Symptoms around this component
Compare staining, odor, sound, temperature and movement with the component operating cycle and nearby materials.
What to document
Photograph the component and the surrounding assembly, note weather or equipment conditions and record whether the symptom is active or historic.
Repair boundary
A visible component may be only one part of a layered detail. Verify interfaces and drainage paths before replacing it in isolation.