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Aviation Technical FAQs

Explore the Technical FAQs

Facet Teflon & Synthetic separator cartridges are cleanable and reusable. They should be inspected and tested before reusing. Cartridge service life should not be extended beyond 3 years. Follow Facet cleaning procedures for Teflon and Synthetic cartridges.

Most elements are a minimum of five years if sealed and in temperature controlled environment. Monitor should be installed within 2 years of shipment from Facet stock.

Coalescer elements must be replaced when:

  1. Filter Membrane (Milipore®) Test indicates elements are not performing (Refer to Section 3).
  2. Corrected Differential pressure exceeds 15 psi or there is a sudden drop in differential pressure.
  3. Continuous sump samples indicate surfactants,
    microbial or solid contaminants.
  4. Free water detection test indicates elements are
    not performing.

Operating a coalescer separator at less than 25% of rated flow, along with extended periods of inactivity, can increase the risk for microbiological growth on the elements due to free water not being released from the coalescer.

Filter/separators   2-4 psid clean at ambient temp.
Micronic Filters    .5-4 psid clean at ambient temp.
2″ Monitors           6-7 psid clean at ambient temp.
6″ Monitors         3-4 psid clean at ambient temp.

Filter/Separators 15 psid
Monitors       15 psid
Micronics          15 psid
“HP”         15 psid
Clays         Based on MSEP test

Filter/Separators 75 psid

Monitors 174 psid

Micronics 75 psid

“HP” 15 psid

Clays N/A

The slug valve stops the flow of product when excessive water is collected in the coalescer separator sump. It works in conjunction with the float control. The slug valve can also be furnished with rate of flow control which is used to control flow through the coalescer separator and with a check valve feature to prevent back-flow.

The water probe detects the level of water electronically and then can open and close the auto water drain valve or slug valve, shut down pump and send alarm to control panel.

The clay treater removes surfactants from fuel to allow coalescer separators to perform properly. The surfactants will disarm the coalescer elements.

The heater keeps water from freezing in the sump and drain lines.

Refer to Application Data Sheet in your catalog.

Canisters have gaskets that improve sealing and have less chance of bypassing. Bags, on the other hand, hold more clay and cost about 40% less.

Not usually. Velcon vessels are built similar to “M” series filter vessels except without adaptors for cartridge sealing. They use center rods, center seals, and end caps. There are conversion kits but are cost prohibitive. Two things to remember, this can be a tremendous selling tool for Facet vessels, but it does add additional cost.

Jet – Clear
AV Gas 100 – Green
AV Gas 100LL – Blue
High Sulfur Diesel – Red.

In most instances, “no.”

Space and ease of maintenance.

Depends on the application. If the customer is having a problem with solids you should definitely have a micronic filter in front of your coalescer separator. The micronic filter is anywhere from a third to a fourth of the cost and has four times the surface area.

  1. Free water is created when the fuel has all the water it can dissolve plus more. This extra water is then free water. Free water is usually not visible as a haze until you get above 30 to 40 ppm free water. This free water is all that a coalescer or absorbent cartridge can remove.
  2. Entrained water: Discrete water droplets carried by a continuous liquid or gas phase when water is immiscible with the liquid. May be separated from the continuous phase by coalescing and gravity separation. Usually picked up in a system by condensation or a water washing used in process.
  3. Dissolved water is the water that is in solution or basically not visible in the fuel. The amount changes with temperature. Fuel holds more water as the temperature increases.

Not really. This is a common misconception. The only true way to tell if the clay is working is to take a MSEP test. This test will be taken on the inlet and the outlet and compared. The reading from the outlet should be higher. A good quality fuel has a reading of 85 or better. The closer you get to 100 the better the fuel quality. If the fuel going in is 80 and the outlet is 80 or less, you would need to change out the clay.

Up to 3-5 pounds per 14″ length dependent upon the micron rating and type of solids present.

The Energy Institute has extended Specification EI 1581 to include Av-Gas that is hydrocarbon based and has aromatics content that is similar to Jet Fuel under Category C sizing and flow.

50 micron, 267 mesh.

No metal components, less expensive while maintaining high efficiency of M Series elements and reduced disposal volume and cost.

Downstream: Yes, the bigger the drops the more the fall. Saves Separator from having to do anything.

Flow per linear inch which is based on EI test (Jet Fuel).


To provide certificate of test data in similar type vessels using flow rates that determine the correct amount of coalescers and separators. Upgrading an older vessel to EI 1581 current edition or changing from competitor vessel to Facet.

Items manufactures by Facet are considered “articles” by definition of the regulations and therefore do not need MSDS sheets.

Per ATA-103 guidelines, drain fuel at maximum practical flow into a suitable container. The vessel must be pressurized, but fuel does not have to be flowing.

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Get in touch with Facet, a part of Filtration Group, to find out more about how our filtration solutions can help you solve your filtration and separation challenges in Aviation, Environmental, Heavy Equipment and Marine processes.


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