AAF International Millennium - Manual (Page 10)

10
7.2 Visible Discharge
1. Improperly Installed or Damaged Bags
Check for holes or tears in bags. Replace damaged bags. Reseal
bags as necessary.
2. Insufficient Dust Cake
The unit could be pulsing too often, resulting in over cleaning.
Verify the pressure drop is at least 2" w.g. Increase the pulse
interval until the unit is operating stably at 2" pressure drop
minimum.
CAUTION: Do not adjust the pulse duration without consulting an
AAF representative.
7.3 Insufficient Hood Control
1. Incorrect Fan Rotation
Incorrect rotation of the fan will result in a failure to provide the
required system static pressure or air volume.
2. Fan V-Belt Slippage
Tighten the V-belts if necessary. Replace broken or
stretched belts.
3. Leaks
Leaking ductwork, access doors, explosion vents, dust discharge
devices, or housing will cause insufficient suction at the pickup
point. Seal any leaks.
4. Closed Air Passages
Clogged ducts, closed dampers, or closed gates will shut off
the airflow.
5. Undersized Ducts
Undersized ducts will create excessive pressure losses for which
the fan may not have been sized. Duct size should be reviewed
considering the design specifications and fan selection.
7.4 Fabric Bag Problems
1. Excessive Temperatures
Operating temperature should not exceed the specified maximum.
2. Humidity
Humidity can blind bags. The moisture results in a denser dust
cake accumulation, or cements dust to the bag. Drawing dry air
through the collector may dry the dust enough to allow the
collector to clean with the fan off. If this method does not work,
the bags must be dry cleaned or new bags installed.
3. Dust Characteristics
Each bag material is selected for specific physical and chemical
characteristics which are compatible with the gas stream
composition and temperature.
4. Dust Buildup In Hoppers
Dust buildup in the hopper may generate a problem in the bag
area and cause excessive abrasion of the bags. The buildup
may be caused by a malfunctioning discharge device, or by
condensation in the hopper. It may be necessary to add a vibrator
to the hopper, or add hopper heaters and insulation.
5. Bag Wear On The Inside
Dirt on the clean side of the bags will cause the bags to wear from
the inside. This could be the result of a broken bag, incorrect bag
installation, or an improper tube sheet seal. Vacuum the clean air
side of the plenum, replace the bag, correct and reseal the bag in
the tube sheet. Do not blow dirt inside the bags. Any dirt contained
in the bags should be vacuumed out.
Part No. Description Recommended Spares
2341881-1 Diaphragm Valve Repair Kit, 10% Number Required
Low Temperature (180°F)
Or
2341881-2 Diaphragm Valve Repair Kit, 10% Number Required
High Temperature (400°F)
2338481-1 Solenoid Valve Repair Kit (NEMA 4) 10% Number Required
5235700 10 Point Printed Circuit Board 1 Timer
5235718 22 Point Printed Circuit Board
5235726 DCP100 Pressure Module
2204493 Fuse 1
5232830 Pulse Pipe Connector Seal, Set (one for each pulse valve)
Low Temperature (to 180°F)
Or
5232848 Pulse Pipe Connector Seal, Set (one for each pulse valve)
High Temperature (to 400°F)
5232194 Pulse Pipe Hairpin (SST) 10% Number Required
When ordering replacement parts, the customer must identify the serial number of the unit, which can be found on the equipment nameplate located adjacent to
the access ladder. To order replacement parts call: 800-477-1214
8.0 Spare Parts
It is recommended that the following spare parts be stored at the installation site for routine maintenance purposes. Consult with your AAF
representative to determine actual quantities required.