How To Use A Vacuum Gauge On Heating Oil Filter

The Vacuum Estimate Tool

By , April 17, 2012

Steve D'Antonio (all)

A properly installed vacuum guess, shown hither adjacent to the filter on the outlet side, is like shooting fish in a barrel to read and doesn't displace the T-handle.

Clients and colleagues effectually the world regularly contact me for aid with onboard systems problems, troubleshooting, or repairs, and, not surprisingly, many of these involve fuel systems.

Recently a customer eastward-mailed me about an engine and generator that would routinely close down when either was heavily loaded, merely otherwise ran well. There were no overt signs of trouble such as leaks or overheating and no apparent electrical problems. When faced with remote troubleshooting, it'due south helpful to place yourself in the position of the person at the other end of the keyboard, cellphone, SSB microphone, or Skype headset. In most cases, these folks aren't trained mechanics and, in spite of many boats beingness well equipped with a full set of tools and spare parts, few carry a truthful complement of engine or systems diagnostic instruments. In many cases I enquire questions that atomic number 82 me, and later them, in the correct direction using the tools at hand.

ATD12-VacGauge03

Top: While this estimate is adequate, ane with a drag, recording, or resettable pointer would allow mechanics to define peak vacuum regardless of the engine's operating condition, and fifty-fifty when it's off. Lesser: A vacuum gauge with a recording needle.

There are a few fuel-system-troubleshooting tools and techniques that y'all tin exploit, straight or remotely, regardless of the skill level of the operator. Main amongst these is the humble fuel-filter vacuum gauge. The vacuum guess is perhaps the single most valuable tool for fuel system assay. Its value as a troubleshooting aid is disproportionate to its meager cost. The best vacuum gauges typically cost less than some oil filters.

Three criteria must exist met to effectively utilize a vacuum judge for fuel system assay or troubleshooting. First, information technology must exist properly installed. Second, the user must understand how information technology works and how to read it. Third, the gauge must be monitored. Typically, vacuum gauges are installed at or near the primary fuel filter. All Racor tandem series filter assemblies include a chemical compound pressure/vacuum gauge. The pressure level portion of the guess is typically not relevant—unless the filter is installed well below alpine fuel tanks that feed from the bottom; in that case, it's possible that the fuel supplying the filters will be nether force per unit area and the guess may indicate this. While this is non harmful and while Racor turbine series filters tin work under as much as 15 psi (0.1 N/mm²) pressure, the manufacturer recommends vacuum or suction applications.

If the master filter is placed nether pressure—either considering of its location and the fuel-tank plumbing arrangement, or considering a priming or auxiliary fuel pump is placed betwixt the filter and the tank and information technology's operated continuously rather than simply for priming—the vacuum gauge may give no indication of filter clogging. The reason is because the vacuum is existence outset by the fuel pressure, creating an equilibrium of sorts. This scenario may be until plenty debris accumulates within the filter element, increasing the vacuum and leading to rapid fuel starvation. To avoid that, tell your customers not to pressurize the chief filter, particularly with an electric pump, while under fashion.

For unmarried Racor or other primary filter installations, the vacuum gauge is all-time installed immediately adjacent to the filter body on the outlet side of the filter. Call back, its primary mission is to measure vacuum between the lift pump on the engine and the filter element. The gauge's main part is to monitor the status of the master fuel filter element. As the chemical element becomes impacted with clay and debris, the level of endeavour required for the engine's fuel lift pump to pull fuel through the filter increases, as does the vacuum imparted on the filter.

As is unremarkably done, installing the vacuum estimate in identify of the filter'due south T admission handle works, and Racor designs the filter for this awarding. I find this installation less than ideal, considering it eliminates the T-handle, making the filter more difficult to service considering you need a wrench. Also, the gauge is more susceptible to damage when the filter is serviced. The gauge should be difficult-plumbed to the filter's outlet fittings (such a fitting is available off the shelf for 900 and 1000 serial filters; a plumbing fixtures must be fabricated for 500 series filters), where it can be safely positioned for piece of cake reading. Alternatively, the guess tin can be remotely plumbed within or exterior the engineroom for more user-friendly reading. For vacuum gauge plumbing runs longer than 12′ (iii.7m), use hard metallic tubing instead of hose.

Gauges equipped with elevate or recording needles or resettable pointers are especially useful, because, later, you can view the record of the highest vacuum experienced past the system. Fuel organisation vacuum is typically greatest when the engine is operating at cruising or full rpm, then checking the vacuum while the engine is idling, or off, will oftentimes reveal little about the condition of the filter element. With a drag needle, the operator no longer needs to clamber into the engineroom while the boat is at cruising speed to define fuel vacuum readings. Installing a recording vacuum estimate is ane of the about cost-effective upgrades you can offer your customers.

Fuel vacuum gauges can often alert boat owners, operators, or service personnel to clogged fuel filters or other fuel supply problems before they become serious. Or, if trouble does come, a vacuum gauge makes the diagnosis easier.

Analyzing and troubleshooting a fuel system with the vacuum judge may seem intuitive, and for the about office it is. If the vacuum increases, the filter needs to exist changed. For the vacuum gauge's readings to be meaningful, you must first plant a baseline with clean filter elements. If, with make clean elements the vacuum is one″ or two″ of mercury, this substantially becomes your "nil set point," and it should be recorded on a tag or label adjacent to the gauge. Anything over that is a issue of clogging or a fault. If the nada set up betoken is high, say above 4″ of mercury (virtually vacuum gauges are calibrated in inches of mercury, anything over well-nigh 7″ is considered high, although most engine manufacturers set their own limits), the system has other resistance-to-flow problems that should be addressed. If no annotation was made of the vacuum with make clean elements with the engine under heavy load, calling on the vacuum approximate to aid troubleshoot an operating problem after will be ineffective. If the system always ran at vii″ of mercury (not good), then this reading may pb to chasing faults that don't exist, or they may exist elsewhere in the system. Loftier vacuum, by the way, tin can lead to reduced fuel lift pump life as well as cavitation erosion inside the injection pump.

In the example mentioned at the commencement of this article (the engine and generator that shut down nether heavy load), I was able to assist the operator identify the trouble using the arrangement's vacuum approximate, but the problem itself was non as straightforward as I had hoped. Initially, based on the loftier vacuum readings in excess of fifteen″ of mercury, I suspected that the fuel filter was chock-full. The client reported that, indeed, it was clogged, so I was confident I'd helped him solve a problem, albeit a minor one. I received a follow-upwards message, however, a day after indicating the problem remained, forth with the excessively high vacuum. After he conducted a few more tests, by drawing fuel from a different tank and monitoring vacuum changes, I concluded the blockage was either in the tank itself at the fuel pickup, or, worse, inside the manifold. Equally it turned out, the blockage—a minor piece of newspaper—was periodically being sucked up into the fuel pickup tube inside one of the tanks. Each time that happened, the vacuum readings skyrocketed, causing the engine and/or generator to shut down. When the engine shut down, the vacuum would dissipate and the newspaper would autumn off the pickup tube. The vacuum gauge saved the mean solar day past making it clear that the problem was between the fuel lift pump and the tank. With that data this part of the fuel arrangement could be carefully scrutinized.

Before the advent of the recording vacuum judge, remotely mounting units at the captain was non uncommon. Now, with the recording feature, that has become less of a necessity.

On a 24-hour interval-to-twenty-four hours ground, a vacuum gauge volition allow your customers to change filters only when necessary, rather than based on a perceived need or, worse, non until their engine begins to run erratically. When more-challenging fuel system problems arise, the vacuum gauge serves as a built-in troubleshooting tool for them and for you.

About the Writer: For many years a full-service g director, Steve now works with gunkhole builders and owners and others in the manufacture as "Steve D'Antonio Marine Consulting Inc." He is the technical editor of Professional person BoatBuilder, and awaits publication (by McGraw-Colina/International Marine) of his volume on marine systems.