Filter Replacement Schedule

Primary Indicator: Pressure Drop Monitoring

The pressure differential across the filter is the most reliable indicator of filter condition:

Pressure Drop	Filter Condition	Action Required
0.5-1.0" WC	Clean (new filter)	Normal operation
2-3" WC	Normal operation	Monitor pressure trend
4-5" WC	Approaching maintenance	Schedule cleaning/replacement soon
6-7" WC	Maintenance threshold	Replace filters THIS WEEK
8+" WC	Critical condition	EMERGENCY: Replace immediately, fan may shut off

Pressure Drop Won't Decrease After Cleaning? This indicates permanent clogging or filter damage - replacement is necessary even if pressure is below 8".

Typical Replacement Intervals

Filter Type	Typical Life	Dust Load Sensitivity
Fiberglass cartridge	6-12 months	High - may need quarterly replacement
Polyester cartridge	12-24 months	Moderate - depends on usage
PTFE-coated cartridge	24-36 months	Moderate - excellent cake release extends life
Aramid (Nomex) bag	24-36 months	Moderate - good for high-temperature use
Polyester bag (standard)	24-48 months	Moderate - baghouse design extends life

Important: These are estimates. Actual life depends heavily on dust load, type, and operation. Pressure drop monitoring is the best indicator regardless of time elapsed.

Cartridge Filter Replacement (15-30 minutes per cartridge)

Step 1: Prepare

• Turn off system (don't pulse while replacing)
• Allow 30 minutes for dust to settle
• Gather new cartridge, tools, and PPE
• Wear dust mask and gloves

Step 2: Access Filter Housing

• Open filter housing lid/door
• Note cartridge orientation (top/bottom seal)
• If equipped with hose, carefully disconnect

Step 3: Remove Old Filter

• Grasp cartridge center, lift straight up
• Don't twist or bend - can damage new filter when reinstalling
• Place old filter in disposal bag
• Inspect housing for cracks or damage

Step 4: Clean Housing

• Use compressed air to blow out dust from housing walls
• Wipe seating surfaces with cloth
• Remove any accumulated dust bridges
• Inspect for debris in bottom of housing

Step 5: Install New Filter

• Verify new cartridge matches old filter specifications
• Check end caps are correct type (open/closed)
• Insert straight into opening, don't tilt
• Push down until seated firmly (should not wobble)
• Reconnect any hose connections

Step 6: Close and Test

• Close housing lid/door securely
• Tighten latches - no air leaks
• Start system and check for air leaks
• Verify pressure drop has decreased to 1-2" WC
• If not, re-seat cartridge or check for problems

Common Mistakes to Avoid

• Wrong cartridge size - cartridge won't seat properly
• Forgetting to remove protective cap on new cartridge
• Not cleaning housing - dust from old filter ruins new one
• Twisting cartridge during installation - can tear media
• Over-tightening latches - can warp housing seals

Maintenance Practices That Extend Filter Replacement Intervals

• Proper pulse jet maintenance: Well-tuned pulse cleaning prevents rapid clogging
• Monitor pulse pressure: Too low = poor cleaning, too high = filter damage
• Use PTFE-coated filters: 30-50% longer life due to better cake release
• Regular housekeeping: Remove settled dust to prevent re-entrainment
• Humidity control: Prevent moisture from caking dust on filters
• Air dryer maintenance: Compressor air should be dry (dew point -40°F or lower)
• Avoid over-cleaning: Excessive pulsing reduces filter life - pulse only when needed
• Temperature control: Keep system well below filter temperature rating

Hazardous Waste Considerations:

• If collecting silica sand dust, filter may be hazardous waste (contains crystalline silica)
• Check local regulations - some require special disposal
• Double-bag filters to contain dust
• Mark bag as containing dust hazard

Recycling Options:

• Metal dust filters can sometimes be recycled for dust content
• Some suppliers offer recycling programs
• Regular industrial waste disposal for most applications
• Never incinerate - can create respiratory hazard