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Universal Silencer P-8 Pre-Filter and P-12F Final Filter

For absolute Filter Elements Used in FASH Series Filter Silencers
Model P-8 Pre-Filter P-12F Final Filter
Part Number 81-0398 [includes #81-0400 polyester pad (1.)] 81-0429
Weight 27 lbs. 47 lbs.
Size 19-1/2" x 24-1/2" x 8" 19-1/2" x 24-1/2" x 11-1/2"
Efficiency Individually tested & certified 85% efficient by N.B.S. Test Individually tested & certified 99.9710 efficient by D.O.P. test for particle size 0.3 Micron & larger
Pressure Drop (Clean) 0.6" H2O at 1250 CFM 1.4" H2O at 1250 CFM
Seal Sponge Neoprene Gasket Silicon Fluid Seal
Filter Media Waterproof Glass
Separators Aluminum
Frame 16 Ga. Galvanealed Steel
Construction Pleated Media Over Corrugated Separators
Tools Required For Removal P / N 80-0457 Removal Tools (2 Required)
(1.) #81-0400 polyester pad is a 2" thick "roughing" filter which fits on the face of the P-8 Pre-Filter. It may be purchased separately in cartons of 12 and should be replaced when visually dirty.
Note: P-8 and P-12Fabsolute filter elements are not cleanable; they must be replaced with new elements per service instructions.
Service Instructions:
filter elements
Filter panels are fragile - handle very carefully by metal frame. Do not touch media. When inserting filters, push on metal frame around edge, not on face of media.
  1. After removing weatherhoods and retainer bar in front of filters, insert filter removal tools in space on either side of Type P-8 Pre-Filter, turning handles 90` so that hook is positioned behind metal flange on front of filter.
  2. Pull evenly on both handles, easing pre-filter out of holding frame. 3. Repeat steps 1 and 2 for removal of final filter.
  1. Be certain inside of filter holding frame is perfectly clean and free of any loose debris.
  2. With fluid-seal-channel end forward, position final filter carefully on spacer bars inside holding frame, pushing it all the way to the back of holding frame. This places fluid seal in contact with "T" frame on rear flange of holding frame. 3. Push pre-filter into place, seating gasket against metal frame of Final Filter. 4. Replace retainer bars and tighten wing screws, replace weatherhoods.

P-8 Pre-Filter and P-12F Final Filter are not cleanable: they must be replaced as prescribed below:

  1. P +' N 81-0400 2" thick polyester pad is to be replaced when visually dirty.
  2. P-8 Pre-Filter should be replaced when pressure drop across it increases 2" H2O over initial clean pressure drop.
  3. P-12F Final Filter should be replaced when pressure drop across it increases 2" H2O over initial clean pressure drop.
Pressure drop increase is determined across P-8 Pre-Filter and P-12F Final Filter individually as follows:
  • When unit is initially installed (filters new), make two pressure drop measure¬≠ments and record results for future reference.
  1. With all filters installed
  2. With P-8 Pre-Filters removed, but with P-12F Final Filters installed.
  • After unit has been in prolonged service and it is necessary to measure pressure drop increases, repeat steps 1 and 2 from (a.) above. Individual in¬≠creases can then be determined by subtracting the clean pressure drops from (a.) from the corresponding pressure drops measured after fitters are loaded.
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