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STS 6004 4 GPM w/Separ Primary Filter -- 110V/60Hz or 230V/50Hz

Your Price: $10199.00

STS 6004 Automated Fuel
Filtration Systems

Ensures Safe & Reliable Emergency Generator Operation

STS 6004 Automated Systems

Click on Graphic to Enlarge

STS 6004
Automated Fuel Filtration Systems


STS 6004

Flow Rates

4 GPM / 240 GPH
(3.2 GPM / 192 GPH for 230V/50Hz)

Tank Size

< 3,000 gal

Port Size

3/4" NPT In & 3/4 " NPT Out


Stainless Steel


110V/60Hz 15A (Standard)
230V/50Hz15A (Optional) **
(Other Voltages Available)

Programable Digital Timer

Programmable, Fully Automated
UL 508A listed Smart Filtration Controller with BMS/BAS Interface and Digital Text Readout


Spur Gear Pump


+/-305 lbs

Dimensions (HxWxD)

36" x 36" x 12"
(91 x 91 x 30 cm)

LG-X Model

LG-X 1500

Primary Filter/Water Separator

Separ SWK-2000/18 Fuel Filter/Water Separator
30 micron (standard)

Secondary Filter Spin-On

Spin On 1, 3, 10 or 25-Micron Particulate
or 3, or 10-micron Water Block

Operating Temperature

41 - 104 deg. F
5 - 40 deg. C

Max. Fluid Viscosity

5 cST

Weatherproof Cabinet

NEMA 12 (IP55), 13 (IP65), 4 (IP66),
3R (IP32) Powder Coat
(Stainless Steel Optional)**

Not for use with fluids that have a flash
point below 100 deg. F (38 deg. C)
(e.g. Gasoline, Alcohol, etc.)

** Choose option during checkout (addition cost may apply)

Available Options

  • STS 6004 OPT-2T -- 2-Tank System

  • STS 6004 STAND -- Unistrut Stand for Cabinet

  • STS 6004 AWD -- Automatic Water Drain

  • STS 6004 HTR -- Cabinet Enclosure Heater - 125 Watt

  • STS 6004 OPT-SS -- Stainless Steel Enclosure

  • STS 6004 CLRS -- Cabinet Color Options

  • STS 6004 EXTWAR -- Extended Warranty Options - Up to Four Years (contact us for more information)

Replacement Filter Options

STS 6004

Separ SWK-2000/18 Fuel Filter/Water Separator

Secondary: Spin-on Filter (standard)

STS 6004 Literature

Articles on Automated Fuel Cleaning

Diesel & Gas Turbine Worldwide - Automated Fuel Cleaning North American Diesel Progress - Automated Fuel Cleaning

The STS-6004 Automated Fuel Filtration System is designed to optimize and maintain diesel fuel indefinitely. Adding an STS 6004 system to your fuel management program will remove particulate, separate water, and condition the fuel. This innovative process stabilizes diesel and bio-fuels, eliminates microbial contamination, and ensures clean reliable fuel at all times.

  • Fully Automated Filtration System

  • Powered by a SMART Filtration Controller (UL508a)

  • Auto Pump Shut Down when Filters Need Service

  • Sensing Fuel Leaks will Shut System Down

  • Alerts Generated When Events Detected:

    • High Water Level in Fuel/Water Separator

    • High Pump Vaccuum

    • High Pump Pressure

    • Low Fuel Flow Detected

  • Maintenance Alert Log File

  • Runtime Totalizer

  • Alarm History Record

  • On-Screen Help

  • Continuous Duty Pump with Viton Seals

  • Powder Coated & Stainless Enclosures

  • Stainless Steel Plumbing

  • Stand Alone, Reliable Turn-Key Equipment

When the Lights Go out ... it is Too Late to Clean Your Tanks.

It is the condition of the fuel in your tanks that determines Engine Performance and Emergency Power Reliability.

Fuel is inherently unstable. It naturally forms sediments, solids and tank sludge. Clogged filters, excessive exhaust smoke, loss of power, and premature damage or failure of fuel injection systems are often symptoms of less than optimal fuel quality causing engines to be unreliable and ultimately fail. Water naturally accumulates in storage tanks due to condensation or leaks in fills and vents. Water and temperature changes create an environment for microbial growth and natural oxidation, accelerating formation of sludge, acids and tank corrosion.

Today's diesel injection systems with pressures of 30,000 psi or more require that the particle size of your fuel does not exceed the tolerances of your engine. Primary filter water-separators dramatically improve engine protection. However, they can only do so much.

In the industry, terms like algae, gum, wax, resin, varnish, tar, asphaltene, etc. are often used to describe the organic contaminant that clogs filters and is responsible for cargo deposits, corrosion, failing injection systems, loss of power, incomplete combustion (black exhaust smoke), and excessive emissions.

A program established to assure continuous optimal fuel quality will reduce overall operating costs

Most Engine Performance Problems
Start in The Fuel Tank

Over the last number of years we have seen a sudden, dramatic and worldwide increase in Filter Plugging Tendencies. What has changed? Oil supply and environmental concerns have resulted in important changes in fuel production, such as cracking, blending, ultra low sulfur, and the introduction of bio-fuels.

These changes have negatively impacted the inherent instability of our fuel and significantly shortened its shelf life. Additives, storage and transportation challenges further accelerate fuel degradation.

Fuel degradation is an inevitable, natural process. And unless an adequate fuel sampling, testing, monitoring and maintenance program is implemented, fuel breakdown will continue to be a potentially expensive liability and a major contributor to your overall operating costs.

Diesel is a very complex fluid. It is not homogenous and no two batches will ever be identical. Fuel deterioration, filterability and shelf life depend on a variety of factors including good housekeeping.

Reliable Power requires the implementation of a unique and innovative Fuel Optimization and Maintenance Technology to adequately protect engines and preserve the integrity of stored fuel beyond filtration and separation.

Recondition, Stabilize and Decontaminate Diesel, Biofuels, Light Oils, and Hydraulic Fluid

The STS 6004 Fuel Filtration Systems are self contained, stand-alone and fully automated. They recondition and stabilize fuel, eliminate & prevent microbial contamination and remove water, sludge and contaminants from tanks; preserving the integrity of stored fuel, providing reliable power whenever it is needed.

STS Installation

Click on Graphic to Enlarge

Implementing STS Fuel Maintenance Systems assures Optimal Fuel Quality & Reliable Engine Performance at all times. It prevents costly downtime, periodic tank cleaning, replacing out of spec fuel and injection system repairs.

The principal components are a continuous duty motor with coupled gear pump, primary filter with vacuum sensor & gauge, Algae-X Fuel Conditioner, and a secondary filter with pressure gauge & sensor. The system is automatically operated by the programmable, UL 508A listed AXI Smart Filtration Controller. All components and control devices are contained within a fully enclosed, lockable, weatherproof NEMA 3R cabinet.

The primary filter protects the pump and removes water and particulate. The secondary filter is a quick change spin-on filter designed to remove emulsified water and contaminants down to 3 Micron.

For safe operation the STS 6004 is equipped with a drip tray monitored by a leak detector. Additional safety elements include automatic system shut-down and indicators when filter elements require service, high pump vacuum exists or a flow interruption is detected.

Fuel Maintenance is an important part of periodic generator maintenance programs – just like changing the oil and ensuring the batteries are charged.

  • Do you have a “Fuel Maintenance Program” in place?

  • Can you afford a clogged filter shutting down your generator?

  • When did you last test your fuel or check the tank for water & sediments?

    • STS 6000 4-GPM Automated Systems

      Click on Graphic to Enlarge

      Both primary and secondary filters are equipped with pressure gauges, water sensors and alarm modules. The programmable UL 508A listed AXI Smart Filtration Controller automatically operates and monitors the STS system. All components and control devices are contained within a fully enclosed, lockable, weatherproof, NEMA certified enclosure.

      For safe operation the STS 6004 is equipped with alarm indicator and system shutdown when filters need service. Additional safety elements include automatic system shut-down in the event of leak detection, water detection in the filter, high pump vacuum, high pump pressure, low fuel flow alert or a flow interruption is detected and flow meter with "no flow" alarm indicator and system shutdown (pressure transmitter).

      The Smart Filtration Controller also provides a maintenance alert log file, runtime totalizer, alarm history and on-screen help.

      STS Systems are available in power configurations for 120 Volt / 60 Hz (15 Amp) or 230 Volt / 50 Hz (15 Amp), and other voltages are available.

      All STS Systems feature multi-stage water removal and particulate filtration, NEMA 12, 13, 3R, 4 Powder Coated or Stainless Steel (optional) enclosure. A unistrut pedestal stand is available for mounting the enclosure up off the floor (standard is for wall mounting), and other colors are also available. All STS 6000 Series Systems are equipped with a UL508a Smart Filtration Controller, and have stainless steel plumbing.

      Additional Optional equipment includes an automatic water drain system and, although the standard STS System is configured for use will one tank, optional configurations allow for use with two tanks.

      A System that will Assure Your Equipment Runs at Peak Efficiency with Optimal Performance

      The STS 6004 Automated Fuel Maintenance System suctions fuel from your storage tank at 240 Gallons per Hour and may be specified for use on up to two separate fuel tanks. Ideally, fuel should be suctioned from the very bottom of the tank, and also from a low point in the tank, or even a tank sump, where water would normally accumulate. Fuel passes through the Separ SWK2000/18 Fuel Filter/Water Separator. This Primary Filtration unit incorporates a five stage filtration scheme. Initially, in Stage One, the fuel passes through the inlet port and flows through the interior vane system which imparts a circular motion to the fuel as it enters the bowl. Then, in Stage Two, the circular direction of the fuel starts the centrifugal motion of the fuel that forces water droplets and heavier particles (down to 30 microns) to the outside wall of the bowl, with the water and particulates eventually settling in the bottom of the bowl. The Separ SWK2000/18 Fuel Filter/Water Separator has the capacity to hold more than 8 ounces of water up to the contacts to the water level probes before the water level alarm will activate. Then, in Stage Three, the fuel passes the vane system positioned on the outside of the central housing. Due to the differing length of the vanes and the twofold rapid change of fuel flow direction, smaller water droplets and finer particulates will settle on the vanes. These settlements will agglomerate and when heavy enough fall to the bottom of the bowl. Already at this point the major portion of any contaminates in the fuel have been separated.

      The Following Guides
      Tell the Story
      •  Understanding Diesel
      Fuel Problems


      •  Fuel Treatment and
      Continuing Management


      •  In-line Fuel Cleaning


      •  Determining What Fuel
      Treatment System
      is Right for You


      •  Cleaning a Fuel Tank

      Just below the filter element, as the fuel enters Stage Four, the flow area of the filter is increased significantly thus reducing the fuel flow rate. This calming effect allows even smaller water droplets and particulate to fall out settling on the inner surfaces of the housing, forming larger droplets which eventually fall into the bottom of the bowl by gravity. Due to the above pre-serration process, the major portion of water and particulate present in the fuel will be in the bowl or on the inner surfaces of the filter, thus greatly extending the filter element life. The final filtration, Stage Five, of the remaining water and particulate still contained in the fuel will be effected by the replaceable filter element, typically utilizing a 60, 30 or 10 micron rated filtration element. These filter elements are produced from a special filter media and are available in different pore sizes. Water Level Probes (Optional) are provided on the glass bowl to sense when the water level in the bowl reaches a critical level. The WATECT Water Sensor (Optional)is monitored by the Controller and will provide an alert when the water level is too high. An Automatic Water Drain is available as an option to automatically discharge the accumulated water from the Primary Filter bowl into a holding container for later disposal.

      A Vacuum Gauge is provided on the top lid of the Separ Fuel Filter/Water Separator to allow for visual monitoring of Vacuum. When the Vacuum reading increases, indicating that the replaceable filter element has reached its capacity for holding particulate material, you know the filter needs changing. No more guessing or changing the filter too soon.

      The clean fuel leaves the filter via the outlet port and passes through the Vacuum Switch connected to the Controller, constantly monitoring vacuum and, upon detection of high vacuum, caused by a clogged Primary Filter or obstruction in the suction line, the Controller will send an alert that high vacuum is occurring, and likely the filter needs replacement. The fuel then continues to the suction size of the Internal Gear Pump. Fuel then exits the pressure port of the pump and passes through a Pressure Switch with Gauge that allows for both visual reading of the pressure in the discharge side of the pump and monitoring of the discharge pressure by the Controller. If discharge pressure is too high, an alert shut down the system. This typically indicates a clogged secondary filter or obstruction in the discharge pipe.

      The fuel flow continues to the AXI Fuel Conditioner. Operating on the principal of induction on the process of combining kinetic and magnetic energy to influence the behavior of electrons, the AXI Fuel Conditioner provides a powerful magnetic field and the flow of fuel provides the kinetic energy.

      As fuel deteriorates, clusters of fuel components break down and residue begins to accumulate, resulting in dark, hazy fuel with poor combustibility. The increase in size and mass of the fuel breakdown products lead to clogged filters and the build up of tank sludge. The AXI Fuel Conditioner dissolves the clusters, stabilizes the fuel, and eliminates tank sludge. The results are Clear & Bright Fuel, improved filterability, optimal combustion and clean fuel systems. The process of how the AXI Fuel Conditioner makes clear, bright and more combustible fuel as well as restoring degraded fuel and eliminating the effects of microbial contamination is compelling. As the AXI Fuel Conditioner does not filter the fuel, but treats it as it passes through the unit, there is seldom any reason to suspect that a restriction is int he AXI Fuel Conditioner. But you can remove the face plate, remove the magnet and wipe it off with a shop rag and replace the filter and face plate. A spare parts kit for the AXI Fuel Conditioner includes a new face panel O-Ring and replacement screws to fasten the face plate.

      The fuel then continues to a Secondary Filtration stage. The Secondary Filter would typically be a ten micron or three micron rated Water Block Filter spin-on element, designed to remove entrained and emulsified water from the fuel stream, or a 10, 3, or 1 micron particulate filter element. A pressure gauge is provided on the Secondary Filter housing to allow for visual monitoring to determine when filter elements require replacement, and a Pressure Switch is provided downstream from the Secondary Filter housing for monitoring by the controller. A restricted Secondary Filter would result in an alert from the Controller of low pressure. Low fuel flow may also cause an alert. Ball valves are provided at the inlet port and outlet port to allow for shutting off fuel flow in the event fuel flows back into the cabinet when filters are being replaced.

      Fuel is then directed back into the storage tank. Ideally, the return line should be at the opposite end of the tank from the suction pipe pickup so that the agitation of the fuel will move water and particulates towards the suction line.

      Leak Detection by way of a float switch in the bottom of the cabinet should the unexpected happen and fuel collects in the sump in the cabinet. Upon detection, the Controller will shut down the system.

      An Enclosure Heater is available as an option for exterior mounting of the STS 6040 Automated Fuel Maintenance System outdoors in cold climates. In cold climates, separate steps should be taken to assure the fuel temperature does not drop below 40 deg. F (5 deg. C) which may result in crystal formation in the fuel thereby clogging filters.