Steve, with respect, I am at a loss trying to understand why you say one could NEVER be alerted to the issues to which you refer on your website. Would not simply opening the drain on a metal filter reveal the problem?
SDA: Much easier to simply look at the bowl than to take periodic samples, you can look at the bowl every time you are in that space.
Plus, those Racor bowls become dirty and very difficult to see through requiring disassembly and cleaning and not to mention when, even clean, it seems a bright LED is required to see in the bowl. I have Racor 500's on each of my two generators. I can't see in the bowls worth a damn and I sure am not going to take them apart.
SDA: Respectfully disagree, I look at a lot of Racor bowls in my work, it's the rare exception to come upon one I can't see through. Agreed, depending upon ER lighting, you may need a flashlight, which isn't much of an inconvenience. Seeing a few inches of water of slimy tendrils in a Racor bowl could be a life saver.
I do have a Racor, with clear bowl, on-engine filter as the final filter. I have attached a picture.
SDA: I don't see it...
I use it not for the clear bowl but for the fact that I can use a 2-micron filter. This is a Lehman 120 engine. The first-in-line on-engine filter is a 3-micron Donaldson.
SDA: The great 2 vs. 10/30 micron primary filter debate had to rear it's head at some point in this discussion;-) What you are doing, and I realize you are not alone, violates almost every engine manufacturer, and Racor's own instructions. Sequetial filtration is more efficient than using a very fine filter as the first step. The subject is covered in detail here
https://stevedmarineconsulting.com/primary-fuel-filters-2-10-30-microns/
In your case, the 1 micron difference probably will make no difference, engine manufacturers choose the micron rating of their secondary filters based on clearances within the injection system, so yours is 3 microns, that's what Lehman determined was needed for adequate clearance, almost certainly with a 100% or 200% safety margin.
I do have an advantage in that my fuel tanks are bottom-feeders. Accumulation of sediment and water is much less likely as I understand the physics.
SDA: I'm not sure I'd agree with that, the bottom feed isn't truly off the tank bottom, it's usually about the same height as a pick up tube, so no real difference with accumulation of debris and water.
In fact, I have drain valves on the two side tanks (360 gal. each) that are one inch lower than the supply line valves.
SDA: OK, so your supply fittings are pretty far off the bottom if the drains are 1" lower?
Every year or so, I open the drain valves to see what comes out. Nothing but fuel, no debris, no water, nothing but clear fuel.
SDA: Unless the drains are on the bottom of the tank, in a well, this isn't terribly definitive, again most drains are accomplished with a welding boss of pipe coupling, to accommodate the flange or weld bead respectively they have to be pretty far above the bottom comparatively. Some photos of the well design here, along with pipe coupling side drains
https://stevedmarineconsulting.com/cleaning-diesel-tanks/
I rather doubt I will ever have a problem with crud but, if I do, an occasional opening of the bottom drain of the primary filter housing will let me know. Bad load of fuel? Highly unlikely as it always was, but with the advent of ULSD diesel and its associated cleanliness requirements for use in high pressure common rail diesels, a bad load of fuel in North America is extremely unlikely, almost non-existent.
SDA: Unlikely but not non-existent, the most common supply contaminant I see in fuel in NA is water.
Sure, Racor turbine filter housings work but I just do not see that they have any particular advantage over a spin-on except maybe the clear bowl, the bowl which one needs a bright light to use.
SDA: Clear bowl, coalescing cone, ease and speed of replacement, water probe, factory provisions for a vacuum gauge using an available outlet plumbing adapter, leak-proof O ring fittings, inexpensive and readily available filter elements, easy and safe to pre-fill...I could go on.
Also, for low volume engines such as Lehmans, doesn't the turbine effect not work?
SDA: It always has an effect, but higher fuel flow does impart more centrifugal force to separate water.
Another point, except in the rare, very rare situation of having to change a filter while underway, changing a spin-on filter is way easier than changing a Racor.
SDA: Having changed hundreds of both in my career, we'll have to agree to disagree.
And, with dual Racors, if both become plugged up underway, now what?
SDA: That's not possible if you are using them correctly, you only run on one at a time, the off line filter can be replaced while underway, so you are back to having a standby in minutes.
A rare occurrence to be sure but, then, plugged filters while underway are rare anyway. Given a choice, I would opt for a Tony Athens sequential filtering system (with vacuum gauges) before a dual Racor any day. One just needs to watch the gauge on the 20-micron first filter to know whether there is crud going on. Then drain once every new fueling to check for water. Done.[/QUOTE]
SDA: As I said, I don't question the effectiveness of the spin on metal filters, and they are less expensive, and with Tony's set up you do get inexpensive sequential filtration, but you could do that with a pair of Racors plumbed in series as well, so no meaningful difference, other than cost, and the Racors offer the other aforementioned attributes.
