Hot swap fuel pre-filters

[mvweebles]

After 1000's of offshore hours running powerboats as an ex delivery skipper doing mostly multi-day runs along the Pacific Coast, I have never had to hot-swap a filter. The dual Racor's are expensive, but good peace of mind. Switch from one to the other, then both if needed (which I have never needed). Ability to hot-swap filters is 'meteorite insurance' only. That said, the Racor 500 is a great filter (single or double) and, despite it's expense (even for a single), is something every cruising sailor should consider. Most sailboats burn less than 1-1/2 gph. Would be very difficult to be caught by surprise with a single 500 installed even with a load of crap fuel.

No one has mentioned water in the fuel which is probably as large a threat as particulate - especially on sailboats where the vent may have been installed in a way that permits water intrusion. With the Racors, water is plainly visible and can be drained off easily.

[mvweebles]

Originally Posted by Q Xopa

My preference is to use 2 x single valves and a T/Y instead of 1 x 3 way valve, to do the same thing.

Cheaper and much easier to find.

The problem I've had with 2-way valves is the plumbing gets complicated quickly, especially with dual tanks which most powerboats have - remember, you have to control not just the supply, but the return. The 3-way valve shown in Post #18 is very nicely done, and is essentially a home-spun version of the Racor 500 Dual Filter setup.

The attached picture uses 2-way valves to control fuel between two tanks and a polishing system. It is a meticulous installation, but with 10-valves visible in the photo, hard to imagine making a change in fuel delivery underway, which is common on longer passages for powerboats.

BTW - one lesson-learned in redoing my fuel system is there are different types of 3-way valves - L-Port and T-Port. Most of the off-shelf 3-way valves I found were L-Port, but the T-Port gives some flexibility that it was worth the effort to source online. An explanation of the difference is seen mid-page HERE.

Contrast that to the attached diagram which is the same setup, but uses Groco 4-Port valves to control supply and return. Premium price (though I found on eBay), but as close to intuitive as possible. Building a quality fuel system is not cheap so it really depends on where you are cruising, how self-sufficient you need your fuel delivery system to be, and your appetite for risk.

[CarinaPDX]

In these parts the need to hot swap filters is not uncommon, especially while crossing the Columbia River bar. Boats that have been sitting for awhile can accumulate water, sediment, and/or algae on the bottom of the tank, and when encountering the rough bar conditions can shake these up and get drawn into the pickup. Keeping the engine running while crossing the bar is rather important...

The last boat I knew that left here, a Union 36, had this happen. I had suggested strongly that he either check the bottom of the tank or get the fuel polished but he decided that carrying a half dozen spare elements was enough. It wasn't. He fouled every one of them in turn and had to be towed into Newport, about 40 miles south.

It is not unusual to collect some condensation at the bottom of the tank, especially in the damp PNW environment. Sometimes fuel comes aboard with water emulsified, which later settles out. Occasionally fuel contains algae, which left untreated can block filters and even hoses. I have intermittently fought algae since early in my cruising. Biocide can kill them, which creates a layer of dead algae that can really play havoc with the fuel system. Better to use Startron, which is an enzyme that dissolves the little guys - much less likely to cause problems. Lucky those that have never had the pleasure...

Greg

[AKA-None]

Couldn’t you use a small pump plumbed in the fuel and the vent going back to the tank. Use that to prime the new second filter?

[David B]

Originally Posted by NWSail

Looking for some advice from someone who has looked into or set this up before...

Currently I have a Parker/Racor120 diesel fuel filter unit inline between the tank and the line that feeds the engine mounted fuel filter, I call this added filter a “pre-filter”. I would like to install a “hot swap” system so there are two pre-filters arranged so that if one becomes clogged I can switch to the other and replace the clogged element without interrupting the fuel flow. It would be nice to also have a gauge that indicates if there is high negative pressure in the fuel line after the filters which would indicate if there is a clogged filter. The setup of this seems simple if a bit parts heavy: two filter units, four shut off valves, a gauge (suggestions?), tubing, elbows, Ts, etc. Here are my questions:

Is there a single integrated unit that will do all of this that is available so I can avoid putting together a system from parts that would have over a dozen connections? I did find an integrated unit but it is designed for high volume fuel flows and is tres expensive. It is rated for 180-360 GPH (1000 MA Series Dual Manifold Marine Diesel Filter--$1500) whereas my engine burns about one liter per hour!

The other question regards what kind of filter to use for this setup. Currently I have a 2 micron engine mounted filter and a 20 micron filter in the Parker/Racor pre-filter. It would be nice to have both 30 and 20 micron pre-filters, but that gets to fussy and has double the parts! Stick with 20 micron in the prefilters and 2 on the engine mounted?

If this has all been discussed before (I searched but did not find an appropriate thread), please feel free to just point me there. Thanks!

The simplest and cheapest system is just a pair of filter housings (if you already have one, then match with another and even cheaper) with an in-line vale at each end, and a 'T' connector before the valves at the inlet and after the valves at the outlet. One off, or both off, is just a matter of flicking a pair of valves.

[NewMoon]

Originally Posted by NWSail

Looking for some advice from someone who has looked into or set this up before...

Currently I have a Parker/Racor120 diesel fuel filter unit inline between the tank and the line that feeds the engine mounted fuel filter, I call this added filter a “pre-filter”. I would like to install a “hot swap” system so there are two pre-filters arranged so that if one becomes clogged I can switch to the other and replace the clogged element without interrupting the fuel flow. It would be nice to also have a gauge that indicates if there is high negative pressure in the fuel line after the filters which would indicate if there is a clogged filter. The setup of this seems simple if a bit parts heavy: two filter units, four shut off valves, a gauge (suggestions?), tubing, elbows, Ts, etc. Here are my questions:

Is there a single integrated unit that will do all of this that is available so I can avoid putting together a system from parts that would have over a dozen connections? I did find an integrated unit but it is designed for high volume fuel flows and is tres expensive. It is rated for 180-360 GPH (1000 MA Series Dual Manifold Marine Diesel Filter--$1500) whereas my engine burns about one liter per hour!

The other question regards what kind of filter to use for this setup. Currently I have a 2 micron engine mounted filter and a 20 micron filter in the Parker/Racor pre-filter. It would be nice to have both 30 and 20 micron pre-filters, but that gets to fussy and has double the parts! Stick with 20 micron in the prefilters and 2 on the engine mounted?

If this has all been discussed before (I searched but did not find an appropriate thread), please feel free to just point me there. Thanks!

Have you considered this one?





$624 at Fisheries Supply. Filters available in 2, 10, or 30 microns.

https://www.fisheriessupply.com/raco...ls-75-b32009-2

I've had it in my current and previous boats. I have always installed the new filter later with engine shut down, but don't see any reason I could not do it with the engine running on the filter I just switched to. I keep a one gallon jug of diesel in the engine room, with which to fill new filters before installing them.

[drcat]

For a design, plumbing layout and how to take a look at most recent Sailing Atticus youtube video. They added second filter on a low budget and show how they primed new filter and got all air out of system.
They are in Caribbean/Panama and are heading for Pacific. They want to have second hot swap filter in case rough weather stirs up gunk in tank or they get dirty fuel someplace which clogs a filter. To give you an idea of how low of a budget they work on, they particle strain diesel they pour into tank thru an old T shirt.

[a64pilot]

Originally Posted by AKA-None

Couldn’t you use a small pump plumbed in the fuel and the vent going back to the tank. Use that to prime the new second filter?

Sure you could, you don’t even need the vent back to the tank, just a momentary switch on the pump and release it when fuel appears out of the filter vent, but your going to need two pumps and or some fancy plumbing to connect the non used filter to both the pump and the tank without drawing fuel from the one in use.
Likely two separate filters and fuel pickups with a selector valve would be the easiest way, many tanks have a separate generator Pickup if you don’t have a generator.
For whatever it’s worth so change out mine on my 4JHE and don’t bleed and it apparently just passes the air bubble though as it’s a self bleeding fuel system

[a64pilot]

Originally Posted by NewMoon

Have you considered this one?





$624 at Fisheries Supply. Filters available in 2, 10, or 30 microns.

https://www.fisheriessupply.com/raco...ls-75-b32009-2

I've had it in my current and previous boats. I have always installed the new filter later with engine shut down, but don't see any reason I could not do it with the engine running on the filter I just switched to. I keep a one gallon jug of diesel in the engine room, with which to fill new filters before installing them.

Only issue I have with those types is the price and availability of filters, Racor 500’s are so numerous and common the filters are easy to find everywhere.

[gold]

Here is a single unit that does it all, plus fuel pump for polishing or backup fuel pressure. https://www.keenanfilters.com/products/

[thereefgeek]

Did this exact thing earlier this year and made a video about it.

https://m.youtube.com/watch?v=aiBYSDzhWvo

In a follow up video I added an electric auxiliary priming and bleeding fuel pump up near the engine-mounted fuel filter.

https://m.youtube.com/watch?v=VAQdDbLO3Us

[timb7734]

Probably this has been covered before ad nauseum:

Per Steve D’Antonio and many manufacturers:
The average 2-micron secondary filter is especially efficient at capturing millions of fine particles until called upon to also capture larger gravel-sized particles as well. The reason for this is straightforward; in spite of their absolute-sounding ratings of 2, 10 and 30 microns, these filters do not possess an absolute ability to capture all particles of their respective ratings and larger. Some larger-sized dirt inevitably slips through. However, because of a phenomenon known as micro-caking, as the filter begins to capture some contaminants, it becomes more efficient at capturing more of the smaller particles — the dirt actually becomes part of the filtering process. If, however, both large and small particles are included in the mix, then the micro-caking process is hindered; the larger “gravel” leaves holes in the caked surface layer, allowing some debris to pass through the (secondary) filter. Picture a bucket with a few holes placed in the bottom; if you pour fine sand into the bucket, some of the sand will filter through the holes, but eventually the sand will capture more new sand than is filtering through the holes. If, however, you poured a mixture of fine sand and gravel into the same bucket, the gravel would keep pathways open for the sand to continue to filter through to the holes in the bottom.

Additionally, operating a 2-micron element as the primary filter means, in theory, all or most of the contamination will be captured in this element and virtually nothing will be captured by the secondary on-engine filter. Thus, you’ve effectively halved your filter media surface area — you now have only one filter that must contend with all of the contamination. If you should happen to take on a batch of particularly dirty fuel, this primary filter may quickly become overwhelmed. If, on the other hand, your primary filter is a 30- or 10-micron rating, then the contamination can be divided between the two filters, offering greater overall media surface area with the finer filter because of the lack of large particles, operating more efficiently to boot. While anecdotal evidence may suggest that 2-micron primary filtration works, this is likely more so the case when dealing with relatively clean fuel. Once comparatively dirty fuel is encountered, segregating the contamination into two locations is simply more efficient and desirable.

Personal experience with a bad load of fuel taken on a week before contamination issues arose, had the 30 micron Racors becoming totally blocked in less than 30 minutes, and the fuel system limiting RPM to idle. The problems arose after a second fueling where we left right away with stirred up tanks.

[Q Xopa]

Originally Posted by thereefgeek

Did this exact thing earlier this year and made a video about it.

In a follow up video I added an electric auxiliary priming and bleeding fuel pump up near the engine-mounted fuel filter.

Nice work! And thanks for sharing.

[Q Xopa]

Originally Posted by gold

Here is a single unit that does it all, plus fuel pump for polishing or backup fuel pressure. https://www.keenanfilters.com/products/

This stuff looks nice!
I cant see a price, but Im thinking its not cheap.

[CarinaPDX]

I agree - that is really nice gear. I don't know that I would want the complexity of an electrically controlled valve or control from a cell phone app. It looks like the products are only available from Keenan and there is no mention of price and the store is down "for updating". Pretty hard to sell anything that way...

Greg