When you use filters, you usually notice their pressure difference goes up little by little over time—that’s ’cause more and more dust piles up in the filter, making it harder for air to pass (so resistance gets higher). But sometimes, the pressure of medium-primary filters drops instead. What’s up with that? Let’s clear this up.
Filter Leaks: If the filter’s pressure difference is lower than when it was new, and it’s already been used for a while, leaks are probably the problem. Leaks mean less resistance, and that makes the pressure difference drop.
Abnormal Pressure Range: Normally, medium-primary filters should have a pressure difference between 30Pa and 120Pa. If it goes below 30Pa, something’s off—you need to check it out and fix it.
Quality Problems: If you just put in a new filter and its pressure difference is way lower than it should be, it might be a dud. Best to check its quality right away, and swap it out if needed.
Measurement Errors: Sometimes the issue’s not the filter—it’s how you’re measuring. If your pressure gauge isn’t calibrated, or you’re using the wrong method, the number you get might be lower than it really is. Double-check both!
These are all the common reasons medium-primary filter pressure drops. If yours is below the normal range, find out what’s causing it, fix it or replace the filter fast. That way, the filter works like it should, and your air stays clean.
