Do Turbine Fuel Filter (water separator) have a MINIMUM flow requirement to be effective?

Question

More to the point can I use a bigger filter unit and still get good water separation? For example the Racor Turbine Series has a small unit (FG500) and much a bigger one (FG1000). The FG 1000 filter element is only marginally more expensive, but has a lot more surface area, so should last longer. However when filtering diesel for an engine that only burns 3L and hour will the increased diameter of the turbine part make for slow spinning fuel and negatively affect the water separation?

Answer 1

A good place to start is by reading the datasheets for the devices, these are ones that i found -

Racor 500 Racor 1000

I see maximum flow rates and pressures, but no minimums, but I didn’t read them fully. You may also want to check that these are the correct filters you are talking about.

This also looks useful for selecting the correct filter. One line in it says “Select a Racor filter that has a greater flow rating than your equipment’s total fuel flow rate.”

Again, there is no minimum flow rate specified -

After that, I would ask the manufacturers to get a definite answer. The datasheet provides their contact details -

Answer 2

From Racor: "A basic answer would be yes. A filter can be too big for an application, affecting performance and efficiency." –

Racor went on to say: "I would not advise the use of the 1000 size based on those engine specs. Even the largest one at 38hp is only going to have a max flow in the realm of 7gph. A single 1000 is rated for 180gph. For efficiency the flow should be at least 45gph. At that flow I would suggest a 500 or a 900 sized unit. " –