I. Most Accurate: Check the differential pressure gauge (recommended)
Primary filter
Normal differential pressure: < 50 Pa
Replacement required: ≥ 100 Pa or double the initial value
Intermediate filter
Normal differential pressure: < 100 Pa
Replacement required: ≥ 200 Pa
High-efficiency filter (HEPA)
Normal differential pressure: < 150 Pa
Replacement required: ≥ 300 Pa or significant decrease in air volume
II. Most Intuitive: Check the appearance
If any of the following conditions are met, it is time to replace the filter:
The filter is blackened, yellowed, or heavily clogged with dust
The filter paper is damaged, leaking, or deformed
The frame seal is detached or cracked
The surface has mold spots, is damp, or has water stains
III. Most Practical: Check the operating effect
When these situations occur, it is basically a clogged filter:
The air supply volume of the equipment decreases, and the blowing sensation weakens
The air outlet is not uniform or even blocked
The door body or box leaks air, makes a whistling sound
The pressure difference in the clean area cannot be maintained
IV. Mandatory Replacement by Time (Backup Plan)
Primary filter: 3 to 6 months
Intermediate filter: 6 to 12 months
High-efficiency filter: 1 to 2 years
(For workshops with a lot of dust, replacement should be done earlier)