Fuel Filter Micron Size

[rustypirate]

diagram of my fuel system plan:

[Sergy]

Thanks everyone for your input and valued opinions.
I have been away from computer and did not expect this much feed back on this matter.
I have decided to go to 30 micron filter on Racor then down to 10 micron on engine.
The first filter before the day tanks is a water separator cartridge with no Micron designation but I imagine it would stop large particles and water.
I thought I was the only one with day tanks so I was pleased to see a diagram.
My return fuel only goes to day tanks and not back to large 200 gallon tanks.
Question I always figured that if I have the day tanks full before the rock and roll (5 hours of motoring)that I should have insurance regarding filter plugged after tanks are stirred up and crap gets dislodged.
Hopefully one could wait till things stopped being stared up before filling the day tanks .One disadvantage of not having the fuel return to main tanks is that the diesel fuel will warm up to engine room temp, but has not been a problem. I MIGHT OF SOLVED ANOTHER PROBLEM I was not able to get full RPM out of engine now I am beginning to think that the 2 micron filter might of prevented 100% flow . Thanks again every one.

[never monday]

Originally Posted by rustypirate

diagram of my fuel system plan:

the output from the polishing pump should have valves to determine which tank it returns to. I don't like it going directly to the engine.

[rustypirate]

Originally Posted by never monday

the output from the polishing pump should have valves to determine which tank it returns to. I don't like it going directly to the engine.

Updated the diagram with arrows and transfer pump:

[Gene :^)]

The only problem I see is that to polish fuel you will need to run the transfer pump and polishing pump at the same time, but if they don't run at the same rate you could either flood the day tank or drain it.

There is no way to continually polish.

Perhaps the polishing pump needs a valve and circuit to draw from the output of the 30 micron but still keep the draw from the day tank for emptying it when storing the boat. You only want to store fuel in the dirty tanks or the day tank will not stay clean.

Or you could put a valve on the output of the transfer pump to direct to either the day tank (for transferring) or to the fuel return, polishing pump output, to storage tanks (for polishing).

[never monday]

Originally Posted by rustypirate

Updated the diagram with arrows and transfer pump:

I would make the polishing operation isolated to the main tanks.

[rustypirate]

OK, what about this?

[Sergy]

BY Polishing do you mean clean the fuel by circulating through the existing filters?
Would not the real nasty fuel be on the bottom of tanks therefore you would want to get at it and move to 2 to 3 Inches above bottom for running of engine

[rustypirate]

If you don't get the nasty stuff at the bottom of the tank, and you have metalic tanks, (aluminum, steel or even stainless) then the water can collect at the bottom and corrode the tank from the inside. Even when running fuel through the engine, you want to pass it through water seperators and filters to get it clean.

Also when underway, the fuel will slosh around and mix the messy part with the remainder, so the pick-up level will not matter that much.

[dohenyboy]

Seaboard Marine - Tony's Tips | Marine Fuel Filtration - “The Seaboard Way”

[never monday]

Originally Posted by rustypirate

OK, what about this?

I like that.. The added touch of filling the day tank is a bonus

[DeepFrz]

I like that article on fuel filtration for newer common rail systems. It even includes new information from an engine manufacturer.

[s/v Jedi]

I would not put any filter between day tank and engine... just the engine-mounted filter. The day tank should have clean fuel, filtered to 2 micron so that the engine mounted filter is doing nothing unless something strange happens: a last line of defense that you hopefully never need.

When you put a filter between day tank and engine you also kill the gravity feed and like reported can even restrict flow so much as to starve the engine which is bad bad I'm told.

You can filter all you like to fill the day tank without any impact on engine.

Here's my diagram; full description here: A new fuel system for Jedi (English) - s/v Jedi


cheers,
Nick.

[rustypirate]

I was under the impression that the fuel filters should allways be on the intake/low-pressure side of pumps to prevent a high-pressure fuel system leak and to allow you to moniter draw on the filter to determine when to change elements.

I guess I could put an additional 2 micron filter after the 30 and 10 micron units, but did not want to restrict the flow too much. I guess I could push the 2 micron unit up to a 500FG to compensate for the reduced flow....

Are you recomending that a single 10-30 micron filter is sufficient for polishing?
Have you found that a 10 micron filter does not get filled too quickly?

[s/v Jedi]

Originally Posted by rustypirate

I was under the impression that the fuel filters should allways be on the intake/low-pressure side of pumps to prevent a high-pressure fuel system leak and to allow you to moniter draw on the filter to determine when to change elements.

You setup would be a bit different because of the day tank. I would love that and might install one in the future.

In my diagram:

• Replace the feed manifold with the day tank.
• Remove transfer pump (you only need one pump but also a backup for it).
• Move the clean fuel tap to the day tank (gravity feed).
• Remove filters between day tank and genset and engine because the fuel in the day tank is already clean.
• Remove pick-up tubes and plumbing between tanks and supply manifold (day tank). Just replace the fittings with a plug.
• Connect fuel return from engine and genset to day tank instead of return manifold.
• Create an "overflow" connection on the day tank that connects to the return manifold. Your return manifold has connections to each tank only.
• Insert a double Racor 500 filter between pump and day tank.
• Don't forget the vent for the day tank.

As you can see the setup becomes much simpler with the day tank. Filling it is the same as polishing; just make sure the valves on the return manifold are set to divert excess clean fuel from the day tank to the storage tank you want.

The pump draws the dirtiest fuel from the tank sumps through the transfer manifold and the first filter. it then pressurizes the fuel to max. 7 psi and pushes it through the 2nd filter with 2 micron elements into the day tank.
The transfer manifold has a tap to drain water and solids (it doubles for pumping from a drum). If I didn't polish for some time, I first drain a bit to check for water/dirt, just to save the filter.

Please note that there might be regulations that do not allow you to have a drain on the bottom of a sump in your tanks. In that case you need a pickup tube from above that goes as far down into the sump as possible (unlike most pick up tubes that stay clear of the sump). You can use a fuel hose instead that lays on the bottom of the tank. You really want to get the water and dirt first so that it can't collect there. It also means you can't use the drain valve on the transfer manifold and everything collects in the first filter.

You do need a spare pump installed and I would choose electric over manual. Just plumb them in parallel and depending on the design you might need a valve in series with each one.

Now for the switches etc. Your pump does 2 things:

1. fill day tank. I would make that automatic with two float switches.
2. polish fuel. I use a mechanical timer switch for this.

Now, if the float switch for empty tank fails, you can use the (timer)switch for polishing fuel to fill the tank instead. If the float switch for full tank fills, it overflows back to a storage tank like if you are polishing fuel. For "tank full" there are accurate pressure switches available (connect to bottom of day tank). There are also ultrasonic sensors that fire from the top of the tank and measure the level that way. Just floats will be fine too especially because the fuel is always clean. Keep the day tank full when not using the engine/genset to prevent condensation. You can use the "clean fuel" tap to check for water if you don't trust it.

I spent a lot of time engineering our fuel system and never found a better system apart from Algae-X stuff etc. that I don't believe in. I copied most from the Nordhavn setup ;-)

I use the enzyme based stabilizers (Star-tron it's called I think).

cheers,
Nick.